State tax docs / States / Wisconsin

Wisconsin state income tax: engine rules, 2026

How the QuantCalc engine computes Wisconsin tax for tax year 2026, rule by rule, with the official source for each rule. Verification status: Worksheet-tested (what this means).

On this page: How the tax is computed · Rate schedule · Deductions, exemptions and credits · Age 65+ subtractions and credits · Social Security · IRA, 401(k) and private pensions · Public pensions · Military retirement pay · Wages · Roth conversions · Capital gains · Blindness and disability · Part-year and nonresident returns · Worked examples · After 2026 · Not calculated · Verification. Machine-readable: this state's entry in the engine config and the provenance file (key WI).

How the tax is computed

Every step the engine takes for Wisconsin, in the order it takes them. Steps marked with a filing status or household type apply only there. Each step links the section below that carries Wisconsin's figures and the official sources for it; the calculation order page describes every step for all jurisdictions.

What each filing status gets, read back from the engine for a household with $1 of income (so below every phase-out and income test):

	Single	Married filing jointly	Married filing separately	Head of household
Rate schedule used	single schedule	joint schedule	own separate schedule	single schedule
Top rate	7.65% from $332,720	7.65% from $443,630	7.65% from $221,820	7.65% from $332,720
Standard deduction, under 65	$13,960	$25,840	$12,280	$18,030
Standard deduction at 70 (joint: both 70)	$13,960	$25,840	$12,280	$18,030
Personal exemption	$700	$1,400	$700	$700
Age subtractions at 70 (joint: both 70)	$250	$500	$250	$250

Per-person mode joint returns with the spouse's age given On a joint return with the spouse's age given, every age test the state applies per taxpayer is evaluated for each spouse at their own age. Without it one household age applies to both.
engine step (compute_state_tax_detail). Engine convention, no external source: The engine cannot know the second spouse's age unless told.
Blindness and disability, per person only when the caller says a person is blind or disabled The filer is person one; the spouse counts only on a joint return and only when the caller says so (there is no household convention as for age). Where a state lets a disabled person (and, where it says so, a blind one, or one whose spouse is disabled) qualify for its general retirement exclusion before the age, that person is treated as having reached the age for that exclusion only. Of the 42 taxing jurisdictions, these have a blind amount: Arizona, Arkansas, California, Colorado, Delaware, the District of Columbia, Hawaii, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, New Jersey, New Mexico, North Dakota, Oklahoma, Oregon, Utah, Vermont and Virginia; these have none: Alabama, Connecticut, Georgia, Louisiana, New York, North Carolina, Ohio, Pennsylvania, Rhode Island, South Carolina, West Virginia and Wisconsin. A disability route is calculated in Arkansas, the District of Columbia, Georgia, Hawaii, Idaho, Iowa, Maryland, Michigan, New Jersey, Oregon and West Virginia.
engine step (compute_state_tax_detail). Engine convention, no external source: Who is blind or disabled is the caller's statement; the engine has no household convention for it.
Rate schedule and standard deduction by filing status Single uses the single schedule and deduction; married filing jointly the joint ones. Head of household and married filing separately follow the two steps below.
Wisconsin's values · engine step (select_brackets). Sources (Rate schedule): 2026 Form 1-ES Instructions (Wisconsin Estimated Tax Voucher Instructions) (checked 2026-10-12)
Married filing separately Where the state publishes its own separate schedule, that one (with half the joint deduction unless a separate deduction is set). Where one schedule applies to every status, that schedule unscaled with the single deduction. Otherwise the joint schedule with every threshold and the deduction halved (computed as the joint tax on twice the income, halved).
Wisconsin's values · engine step (select_brackets). Sources (Rate schedule): 2026 Form 1-ES Instructions (Wisconsin Estimated Tax Voucher Instructions) (checked 2026-10-12)
Head of household The state's head-of-household schedule where it has one, else the single schedule; the head-of-household deduction where set, else the single deduction.
Wisconsin's values · engine step (select_brackets). Sources (Rate schedule): 2026 Form 1-ES Instructions (Wisconsin Estimated Tax Voucher Instructions) (checked 2026-10-12)
A separate deduction for married filing separately married filing separately Where set, this amount replaces the deduction the schedule rule above gives married filing separately.
Wisconsin's values · engine step (compute_state_tax_detail). Sources (Deductions, exemptions and credits): 2026 Form 1-ES Instructions (Wisconsin Estimated Tax Voucher Instructions) (checked 2026-10-12); Wisconsin Department of Revenue: 2025-Schedule2440W.pdf (checked 2026-10-12); Wisconsin Department of Revenue: 2025-ScheduleSB-Inst.pdf (checked 2026-10-12); 2025 Wisconsin Form 1 Instructions (checked 2026-10-12); Wis. Stat. ch. 71 (2023-24 Wis. Stats. updated through 2025 Wis. Act 87, published 3-1-26) (checked 2026-10-01); 2025 Wisconsin Schedule H/H-EZ Instructions (Homestead Credit) (checked 2026-10-12); 2025 Wisconsin Schedule H, Homestead Credit Claim (checked 2026-10-12)
The income total every income test uses Other ordinary income + retirement distributions (before any exclusion) + conversion + federally taxable Social Security + long-term gains + Railroad Retirement Tier 2. It stands in for federal adjusted gross income in every threshold, cliff and phase-out below; state subtractions do not reduce it.
engine step (compute_state_tax_detail). Engine convention, no external source: The inputs are the federal AGI components, so their sum is federal AGI for these income types.
Attributing income to each spouse joint returns with each spouse's own amounts given With a caller's split (the API's spouse object), each spouse's own distributions (employer-plan money included), pension, public pension, conversion, wages and military pay; spouse 2's shares are clamped into the household totals and spouse 1 gets the rest. Without a split, in per-person mode, every item is divided 50/50. Social Security is divided by each spouse's own gross benefits where the caller gives spouse.socialSecurityGross, else 50/50; other ordinary income and gains are always divided 50/50 where a rule needs a per-person amount. The split is used only where a state's rule is per taxpayer; household totals stay authoritative for the base and the income tests.
engine step (compute_state_tax_detail). Engine convention, no external source: Equal attribution is the neutral split when the owner of a dollar is not known.
Early IRA distributions The IRA and employer-plan dollars each person took before 59½: the amount the caller gave, else every such dollar of a person under 59 at the end of the year (none of an older person, or when the age is not given). Where the state keeps its retirement break only for some federal early-withdrawal exceptions, the other early dollars leave the retirement pool and are taxed as ordinary income; the exception is the caller's, else death for a survivor's benefits, disability for a disabled person, else none. Where the state taxes only the part over the IRA basis, the part within it is left out altogether. A kept exception passes the state's IRA age gate. The additional state tax on the early dollars with no exception is added before the credits, or after them where the state says so (next steps).
Wisconsin's values · engine step (compute_state_tax_detail). Sources (IRA, 401(k) and private pensions): 2025 Wisconsin Schedule SB Instructions (Subtractions from Income) (checked 2026-10-12); Tax Practitioner Fall 2025 Questions and Answers (checked 2026-10-12); Publication 126: How Your Retirement Benefits Are Taxed (checked 2026-10-12); 2025 Wisconsin Schedule SB Instructions (Subtractions from Income) (checked 2026-10-12); 2025 Wisconsin Form 1 instructions (checked 2026-10-12)
Disability pay only when the caller gives the person facts (a civil service annuity, disability pay, Social Security disability, survivor benefits, an IRA basis or an exception) Each person's disability pay (the caller's disabilityIncome, part of the pension income) is excluded up to the state's cap (all of it where there is none), for a totally and permanently disabled person where the state requires it and below the age where there is one; on a joint return without per-person amounts the cap is doubled only when a second person can qualify (the spouse also said to be disabled where the state requires it). Where the state reduces it, the total is reduced dollar for dollar by the return's income over the threshold (one threshold per return; the separate-return threshold where there is one). The excluded dollars leave the base before any retirement exclusion. Where the state reads it, the plan's minimum retirement age (when given) replaces the age at which the pay stops being excluded.
Wisconsin's values · engine step (compute_state_tax_detail). Sources (Blindness and disability): Wisconsin Department of Revenue: 2026-Form1-ES-Inst.pdf (checked 2026-10-12); Wisconsin Department of Revenue: 2025-Schedule2440W.pdf (checked 2026-10-12); Wisconsin Department of Revenue: 2025-ScheduleSB-Inst.pdf (checked 2026-10-12)
Keeping the per-spouse shares inside the household joint returns with each spouse's own amounts given After the public-pension and employer-pension carve-outs, if the two spouses' remaining shares add up to more than the household's exclusion-eligible distributions (an inconsistent split), spouse 1's share is reduced so they do not.
engine step (compute_state_tax_detail). Engine convention, no external source: Input normalisation.
Military retirement pay The state's military rule runs first, on military pay alone, per taxpayer: each spouse's own pay at their own age when attributed, otherwise half each at the household age on a joint return. Exempt dollars leave the base; the rest become pension dollars for the general retirement rules. Where the state lets a disabled retiree qualify at any age, a disabled person is treated as having reached the rule's age.
Wisconsin's values · engine step (compute_state_tax_detail). Sources (Military retirement pay): Pcs retired (checked 2026-09-27)
One taxpayer's military exemption Exempt: all of it (below the age split, up to the younger cap). Capped: up to the cap for the age tier, plus the earned-income bonus below the age split when the taxpayer's own wages exceed the threshold, less the taxpayer's own Social Security where the rule says so. Percentage: the percentage (below the age split, up to the younger cap). Then the income limit: above it the exemption is lost, or phased out over the range where one is set.
Wisconsin's values · engine step (military_exempt_one). Sources (Military retirement pay): Pcs retired (checked 2026-09-27)
Capital-loss deduction off the base The deduction comes off the other ordinary income (negative income, as Form 1040 line 7a is), so the base and every state-AGI figure summed from it carry it; WI no more than Wisconsin ordinary income (Schedule WD line 28(c)). States whose base is federal taxable income (with the caller's figure) already have it there and take it only once. Engine 1.13.1: the allowed rental loss comes off the same way, on its own line (rental_loss_deduction).
Wisconsin's values · engine step (compute_state_tax_detail). Sources (Capital gains): 2025 Wisconsin Schedule WD Instructions (Capital Gains and Losses) (checked 2026-10-12); 2025 Schedule WD (Capital Gains and Losses) (checked 2026-10-12); 2025 Schedule WD Instructions (checked 2026-10-12)
Social Security exempt None of the federally taxable benefit enters the base.
Wisconsin's values · engine step (ss_amount_in_state_base). Sources (Social Security): 2025 Wisconsin Schedule SB Instructions (Subtractions from Income) (checked 2026-10-12); Publication 126: How Your Retirement Benefits Are Taxed (checked 2026-10-12)
Does a conversion draw the retirement cap? Where the state lets a conversion draw the capped exclusion, and the filer is at or above the conversion age (the state's own pooling age where it has one; any age for a disabled person where the state says so), the conversion is pooled with distributions against the cap. A spouse who elects not to claim the exclusion draws none of it.
Wisconsin's values · engine step (compute_state_tax_detail). Sources (Roth conversions): 2025 Wisconsin Form 1 Instructions (checked 2026-10-12); Tax Practitioner Fall 2025 Questions and Answers (checked 2026-10-12)
Retirement exclusion per spouse (both ages known) joint returns with the spouse's age given Full-exclusion states exclude each qualifying spouse's own dollars. Capped states give each spouse the single cap for their own age against their own eligible dollars (pension dollars only where the exclusion is pension-only; employer dollars only below the IRA age), less their military exclusion and their own Social Security offset (by the spouse's stated gross benefits, else half). Per-return states (and the pooled-if-both-qualify rule when both qualify) apply the joint cap to the couple's pooled eligible dollars when either spouse qualifies. The income tests then apply once to the summed deduction.
Wisconsin's values · engine step (compute_state_tax_detail). Sources (IRA, 401(k) and private pensions): 2025 Wisconsin Schedule SB Instructions (Subtractions from Income) (checked 2026-10-12); Tax Practitioner Fall 2025 Questions and Answers (checked 2026-10-12); Publication 126: How Your Retirement Benefits Are Taxed (checked 2026-10-12); 2025 Wisconsin Schedule SB Instructions (Subtractions from Income) (checked 2026-10-12); 2025 Wisconsin Form 1 instructions (checked 2026-10-12)
Conversion pooled with distributions The conversion joins the distributions against the one cap (with a spouse split in a per-taxpayer state, each spouse's own distributions and conversion against that spouse's cap). Nothing of the conversion is added separately.
Wisconsin's values · engine step (compute_state_tax_detail). Sources (Roth conversions): 2025 Wisconsin Form 1 Instructions (checked 2026-10-12); Tax Practitioner Fall 2025 Questions and Answers (checked 2026-10-12)
Retirement exclusion (household) The distributions eligible for the exclusion go through the exclusion below. Taxable public-pension dollars left by a cap are not eligible; below the IRA age only employer-plan dollars are.
Wisconsin's values · engine step (compute_state_tax_detail). Sources (IRA, 401(k) and private pensions): 2025 Wisconsin Schedule SB Instructions (Subtractions from Income) (checked 2026-10-12); Tax Practitioner Fall 2025 Questions and Answers (checked 2026-10-12); Publication 126: How Your Retirement Benefits Are Taxed (checked 2026-10-12); 2025 Wisconsin Schedule SB Instructions (Subtractions from Income) (checked 2026-10-12); 2025 Wisconsin Form 1 instructions (checked 2026-10-12)
Conversion taxed or exempt In full-exclusion states a conversion is exempt at the qualifying age (at any age where the state says so). Elsewhere, unless pooled above, it is ordinary income taxed in full.
Wisconsin's values · engine step (compute_state_tax_detail). Sources (Roth conversions): 2025 Wisconsin Form 1 Instructions (checked 2026-10-12); Tax Practitioner Fall 2025 Questions and Answers (checked 2026-10-12)
Cap by age tier The full cap at or above the exclusion age, the lower cap at or above the partial age, otherwise none. Joint returns use the joint cap; every other status the single cap.
Wisconsin's values · engine step (retirement_distributions_in_state_base). Sources (IRA, 401(k) and private pensions): 2025 Wisconsin Schedule SB Instructions (Subtractions from Income) (checked 2026-10-12); Tax Practitioner Fall 2025 Questions and Answers (checked 2026-10-12); Publication 126: How Your Retirement Benefits Are Taxed (checked 2026-10-12); 2025 Wisconsin Schedule SB Instructions (Subtractions from Income) (checked 2026-10-12); 2025 Wisconsin Form 1 instructions (checked 2026-10-12)
The capped deduction Deduction = the smaller of the eligible distributions and the cap, then reduced by the income limit above; the rest of the distributions stays in the base.
Wisconsin's values · engine step (retirement_distributions_in_state_base). Sources (IRA, 401(k) and private pensions): 2025 Wisconsin Schedule SB Instructions (Subtractions from Income) (checked 2026-10-12); Tax Practitioner Fall 2025 Questions and Answers (checked 2026-10-12); Publication 126: How Your Retirement Benefits Are Taxed (checked 2026-10-12); 2025 Wisconsin Schedule SB Instructions (Subtractions from Income) (checked 2026-10-12); 2025 Wisconsin Form 1 instructions (checked 2026-10-12)
One taxpayer's cap joint returns with the spouse's age given For per-spouse calculations, each spouse's cap is the single-column cap for their age tier.
Wisconsin's values · engine step (per_taxpayer_cap_single). Sources (IRA, 401(k) and private pensions): 2025 Wisconsin Schedule SB Instructions (Subtractions from Income) (checked 2026-10-12); Tax Practitioner Fall 2025 Questions and Answers (checked 2026-10-12); Publication 126: How Your Retirement Benefits Are Taxed (checked 2026-10-12); 2025 Wisconsin Schedule SB Instructions (Subtractions from Income) (checked 2026-10-12); 2025 Wisconsin Form 1 instructions (checked 2026-10-12)
Long-term gains in the base Where gains are taxed as ordinary income: net long-term gain less the flat exclusion (never below zero), times the inclusion share. Elsewhere none enters.
Wisconsin's values · engine step (compute_state_tax_detail). Sources (Capital gains): 2025 Wisconsin Schedule WD Instructions (Capital Gains and Losses) (checked 2026-10-12); 2025 Schedule WD (Capital Gains and Losses) (checked 2026-10-12); 2025 Schedule WD Instructions (checked 2026-10-12)
Low-income retirement income subtraction While the income total is less than the status limit, each person at or above the age subtracts the pension and IRA dollars still in the base, up to the amount (per spouse with their own amounts; on the household path at the household age, twice the amount on a joint return). Not on a separate return, whose limit is both spouses' combined income. It does not forfeit the credits.
Wisconsin's values · engine step (compute_state_tax_detail). Sources (IRA, 401(k) and private pensions): 2025 Wisconsin Schedule SB Instructions (Subtractions from Income) (checked 2026-10-12); Tax Practitioner Fall 2025 Questions and Answers (checked 2026-10-12); Publication 126: How Your Retirement Benefits Are Taxed (checked 2026-10-12); 2025 Wisconsin Schedule SB Instructions (Subtractions from Income) (checked 2026-10-12); 2025 Wisconsin Form 1 instructions (checked 2026-10-12)
Standard deduction phase-out Above the start the deduction is scaled by 1 − (income − start) / width, down to zero, with head-of-household and separate starts where the state has them; where the state says so a head of household never gets less than the single deduction at the same income. Where the state rounds the reduction, it is rounded down to that multiple before it is taken. Where the state says so the income is its own (the base after its subtractions) rather than the income total.
Wisconsin's values · engine step (compute_state_tax_detail). Sources (Deductions, exemptions and credits): 2026 Form 1-ES Instructions (Wisconsin Estimated Tax Voucher Instructions) (checked 2026-10-12); Wisconsin Department of Revenue: 2025-Schedule2440W.pdf (checked 2026-10-12); Wisconsin Department of Revenue: 2025-ScheduleSB-Inst.pdf (checked 2026-10-12); 2025 Wisconsin Form 1 Instructions (checked 2026-10-12); Wis. Stat. ch. 71 (2023-24 Wis. Stats. updated through 2025 Wis. Act 87, published 3-1-26) (checked 2026-10-01); 2025 Wisconsin Schedule H/H-EZ Instructions (Homestead Credit) (checked 2026-10-12); 2025 Wisconsin Schedule H, Homestead Credit Claim (checked 2026-10-12)
Personal exemption The joint amount on a joint return, the head-of-household amount where set, otherwise the single amount.
Wisconsin's values · engine step (compute_state_tax_detail). Sources (Deductions, exemptions and credits): 2026 Form 1-ES Instructions (Wisconsin Estimated Tax Voucher Instructions) (checked 2026-10-12); Wisconsin Department of Revenue: 2025-Schedule2440W.pdf (checked 2026-10-12); Wisconsin Department of Revenue: 2025-ScheduleSB-Inst.pdf (checked 2026-10-12); 2025 Wisconsin Form 1 Instructions (checked 2026-10-12); Wis. Stat. ch. 71 (2023-24 Wis. Stats. updated through 2025 Wis. Act 87, published 3-1-26) (checked 2026-10-01); 2025 Wisconsin Schedule H/H-EZ Instructions (Homestead Credit) (checked 2026-10-12); 2025 Wisconsin Schedule H, Homestead Credit Claim (checked 2026-10-12)
Dependent exemptions and deductions only when the caller lists dependents An amount per dependent subtracted like the personal exemption: the state's flat amount, or the stepped per-exemption amount the filer gets, or the state's own income steps; nothing above an income limit where there is one; a percentage phase-out per income step where there is one; one more for a dependent in an age band or a student up to an age, for a dependent born in the year, and for a disabled dependent; a deduction per dependent beyond the first on joint and head-of-household returns; and a child deduction by an income table for dependents under an age. A head of household's status exemption that already holds one dependent's amount counts one fewer. Where the state says so, the phase-out is measured on the state AGI (the base before deductions).
Wisconsin's values · engine step (compute_state_tax_detail). Sources (Deductions, exemptions and credits): 2026 Form 1-ES Instructions (Wisconsin Estimated Tax Voucher Instructions) (checked 2026-10-12); Wisconsin Department of Revenue: 2025-Schedule2440W.pdf (checked 2026-10-12); Wisconsin Department of Revenue: 2025-ScheduleSB-Inst.pdf (checked 2026-10-12); 2025 Wisconsin Form 1 Instructions (checked 2026-10-12); Wis. Stat. ch. 71 (2023-24 Wis. Stats. updated through 2025 Wis. Act 87, published 3-1-26) (checked 2026-10-01); 2025 Wisconsin Schedule H/H-EZ Instructions (Homestead Credit) (checked 2026-10-12); 2025 Wisconsin Schedule H, Homestead Credit Claim (checked 2026-10-12)
Age subtraction At or above the age: the single amount, or the joint amount on a joint return (both spouses at the household age). In per-person mode, half the joint amount (or the single amount) per qualifying spouse. Plus the low-income amount below the income test; less the military exclusion where the statute says so; limited to the spouse's own income where the statute says so. Where the statute counts income from any source, the taxable remainder of the spouse's own public pension is part of that own income. Where the state says so, the Social Security that offsets a person's amount is that person's own.
Wisconsin's values · engine step (compute_state_tax_detail). Sources (Age 65+ subtractions and credits): 2026 Form1 ES Inst (checked 2026-10-12)
State taxable income Other ordinary income + Social Security, retirement income, conversion and gains left in the base − standard deduction − personal exemption − age subtractions.
engine step (compute_state_tax_detail). Engine convention, no external source: The order of subtraction follows the state forms; each amount is sourced at its own step.
No tax at or below zero State taxable income at or below zero returns a tax of 0 (credits are not refundable), unless the state has a tax computed apart from taxable income that still applies (next step).
engine step (compute_state_tax_detail). Engine convention, no external source: Every credit the engine carries is nonrefundable, so nothing below can make a zero tax negative; each credit is sourced at its own step.
Separate-return scaling married filing separately For the halved-joint rule, taxable income is doubled before the schedule and the result halved.
Wisconsin's values · engine step (compute_state_tax_detail). Sources (Rate schedule): 2026 Form 1-ES Instructions (Wisconsin Estimated Tax Voucher Instructions) (checked 2026-10-12)
The rate schedule Each bracket's rate on the part of taxable income inside it, summed. No rounding: the result is carried in full precision.
Wisconsin's values · engine step (apply_state_brackets). Sources (Rate schedule): 2026 Form 1-ES Instructions (Wisconsin Estimated Tax Voucher Instructions) (checked 2026-10-12)
Additional tax on early distributions The state's share of the federal additional tax on early distributions (the rate on each early dollar with no exception): added before the credits (Arkansas, Nebraska, Vermont), or after them in California and Wisconsin (see the step after the credits).
Wisconsin's values · engine step (compute_state_tax_detail). Sources (IRA, 401(k) and private pensions): 2025 Wisconsin Schedule SB Instructions (Subtractions from Income) (checked 2026-10-12); Tax Practitioner Fall 2025 Questions and Answers (checked 2026-10-12); Publication 126: How Your Retirement Benefits Are Taxed (checked 2026-10-12); 2025 Wisconsin Schedule SB Instructions (Subtractions from Income) (checked 2026-10-12); 2025 Wisconsin Form 1 instructions (checked 2026-10-12)
Married couple credit joint returns with each spouse's own amounts given Joint returns with the spouse's age and a spouse split only, and only when no retirement exclusion was taken: the rate times the lower-earning spouse's wages, up to the maximum.
Wisconsin's values · engine step (compute_state_tax_detail). Sources (Wages): 6 (checked 2026-09-27); Pcs retired (checked 2026-09-27)
Credits cannot make the tax negative The credits are subtracted and the result floored at zero.
engine step (compute_state_tax_detail). Engine convention, no external source: Every credit the engine carries is nonrefundable; each credit is sourced at its own step.
Qualifying surviving spouse qualifying surviving spouse returns A qualifying surviving spouse (filingStatus qss) is one person on the return, taxed from the single figures with the state's own treatment of the status laid over them: where the state says so, the joint rate schedule, the joint standard deduction, the joint personal exemption, the joint income limits and phase-outs (only those the state sets for joint returns), the married 65+ and blindness amounts, or the head-of-household return; where the state gives the status nothing of its own, the single return. The federal figures the engine derives for the status are the federal qualifying-surviving-spouse ones (the joint standard deduction, the married 65+ amount).
Wisconsin's values · engine step (state_tax_effective_config). Sources (Rate schedule): 2026 Form 1-ES Instructions (Wisconsin Estimated Tax Voucher Instructions) (checked 2026-10-12)
Elections: claim the exclusion or not Where claiming a retirement exclusion costs a credit, the engine computes the return each way and keeps the lower tax (on a tie, the exclusion is claimed). Arkansas: the "65 Special" credit goes only to a 65+ taxpayer who claims no retirement exemption, so each such taxpayer (per person with both ages or a per-taxpayer split, else the return) may forgo the exemption. Wisconsin: the 67+ retirement subtraction forfeits the credits, so on a joint return with the spouse's age and own amounts the return without the subtraction (and with the married couple credit) is weighed against the return with it.
Wisconsin's values · engine step (compute_state_tax_detail). Sources (IRA, 401(k) and private pensions): 2025 Wisconsin Schedule SB Instructions (Subtractions from Income) (checked 2026-10-12); Tax Practitioner Fall 2025 Questions and Answers (checked 2026-10-12); Publication 126: How Your Retirement Benefits Are Taxed (checked 2026-10-12); 2025 Wisconsin Schedule SB Instructions (Subtractions from Income) (checked 2026-10-12); 2025 Wisconsin Form 1 instructions (checked 2026-10-12)
Railroad Retirement benefits only when the caller gives Railroad Retirement benefits Railroad Retirement benefits are never taxed by a state (45 U.S.C. §231m). Tier 2 (railroadRetirementTier2) is in the income total the tests use but never in the base. Tier 1 (railroadRetirementTier1) is a part of the gross benefits (socialSecurityGross); its share of the taxable benefits is taken out of the Social Security every state rule sees, so a state that taxes Social Security never reaches it. Where a state's worksheet says so, the benefits reduce a retirement cap or subtraction (ID, IN, MD, ME, MN: both tiers; MI: the taxable railroad benefits); Minnesota's and Utah's Social Security rules test an income without them, Minnesota's, New Jersey's and California's retirement income tests an income without Tier 2; Ohio and Delaware test their own AGI everywhere, which never holds the benefits.
Wisconsin's values · engine step (compute_state_tax_detail). Sources (Social Security): 2025 Wisconsin Schedule SB Instructions (Subtractions from Income) (checked 2026-10-12); Publication 126: How Your Retirement Benefits Are Taxed (checked 2026-10-12)
The capital-loss deduction the state allows With a net capital loss (capitalLoss): the smaller of the loss and the state's limit (the federal $3,000 / $1,500 where the state follows the federal return; MA $2,000, and no more than the interest and dividends); AL the loss less the part carried in, unlimited; PA and NJ none. It comes off the income total the income tests use (and the Social Security worksheets' income); the gross-income filing test (LA) reads the total before it. Engine 1.13.1: with a rental loss (rentalNetIncome below 0, the federal Schedule E line 26 amount) the state allows, the whole loss where the state starts from federal AGI or follows the federal schedule, none in PA and NJ (rental_loss_no_offset): it comes off the same income the same way; a rental profit is other ordinary income.
Wisconsin's values · engine step (compute_state_tax_detail). Sources (Capital gains): 2025 Wisconsin Schedule WD Instructions (Capital Gains and Losses) (checked 2026-10-12); 2025 Schedule WD (Capital Gains and Losses) (checked 2026-10-12); 2025 Schedule WD Instructions (checked 2026-10-12)
Each spouse's own Social Security joint returns On a joint return, each spouse's own Social Security is the spouse's share of the benefits by spouse.socialSecurityGross when the caller gives it (Tier 1 railroad benefits left out), else half each. It is what the per-spouse rules read: Colorado's per-spouse subtraction, Rhode Island's per-spouse modification, and the Maine, Maryland and other retirement caps reduced by the benefits each spouse received (with each spouse's own railroad benefits where the state counts them).
Wisconsin's values · engine step (compute_state_tax_detail). Sources (Social Security): 2025 Wisconsin Schedule SB Instructions (Subtractions from Income) (checked 2026-10-12); Publication 126: How Your Retirement Benefits Are Taxed (checked 2026-10-12)
Taxes that survive a zero taxable income Where the state's forms compute them apart from taxable income, the early-distribution tax, the minimum tax and the capital-gains surcharge still apply when taxable income is zero or less: the return goes on with taxable income 0 (no schedule tax), and only the credits the state allows against them reduce them.
Wisconsin's values · engine step (compute_state_tax_detail). Sources (Rate schedule): 2026 Form 1-ES Instructions (Wisconsin Estimated Tax Voucher Instructions) (checked 2026-10-12)
Early-distribution tax after the credits Where the state adds its early-distribution tax after the nonrefundable credits (California, Wisconsin), it is added to the tax left after them, so no credit offsets it.
Wisconsin's values · engine step (compute_state_tax_detail). Sources (IRA, 401(k) and private pensions): 2025 Wisconsin Schedule SB Instructions (Subtractions from Income) (checked 2026-10-12); Tax Practitioner Fall 2025 Questions and Answers (checked 2026-10-12); Publication 126: How Your Retirement Benefits Are Taxed (checked 2026-10-12); 2025 Wisconsin Schedule SB Instructions (Subtractions from Income) (checked 2026-10-12); 2025 Wisconsin Form 1 instructions (checked 2026-10-12)
Refundable state credits The credits paid beyond the tax (reported in refundableCredits; netTax = totalTax less them): earned income credits as a share of the federal EIC with each state's own age band (OK on the 2020 federal credit, DC's own childless schedule, the CalEITC table, MN's Working Family Credit), the NYC EIC and school tax credits, and the property-tax, renter, grocery and senior credits of MA, MI, NJ, ID, HI, NM, OK, AZ, NY, RI, WV, ME, DC, MN, MO, WI, IN and MT, each on its own income measure. Engine 1.13.1: a part-year NYC resident's school tax credits (the Table 2 proration chart and the rate-reduction amount on IT-360.1 line 47; IT-203 lines 60 / 60a for a part-year state resident).
Wisconsin's values · engine step (state_tax_refundable_credits). Sources (Deductions, exemptions and credits): 2026 Form 1-ES Instructions (Wisconsin Estimated Tax Voucher Instructions) (checked 2026-10-12); Wisconsin Department of Revenue: 2025-Schedule2440W.pdf (checked 2026-10-12); Wisconsin Department of Revenue: 2025-ScheduleSB-Inst.pdf (checked 2026-10-12); 2025 Wisconsin Form 1 Instructions (checked 2026-10-12); Wis. Stat. ch. 71 (2023-24 Wis. Stats. updated through 2025 Wis. Act 87, published 3-1-26) (checked 2026-10-01); 2025 Wisconsin Schedule H/H-EZ Instructions (Homestead Credit) (checked 2026-10-12); 2025 Wisconsin Schedule H, Homestead Credit Claim (checked 2026-10-12)
School property tax credit (WI) Form 1 lines 16a-16b: a share of the property taxes plus rent constituting property taxes, the base at most $2,500 (half on a separate return), nonrefundable.
Wisconsin's values · engine step (st_compute). Sources (Deductions, exemptions and credits): 2026 Form 1-ES Instructions (Wisconsin Estimated Tax Voucher Instructions) (checked 2026-10-12); Wisconsin Department of Revenue: 2025-Schedule2440W.pdf (checked 2026-10-12); Wisconsin Department of Revenue: 2025-ScheduleSB-Inst.pdf (checked 2026-10-12); 2025 Wisconsin Form 1 Instructions (checked 2026-10-12); Wis. Stat. ch. 71 (2023-24 Wis. Stats. updated through 2025 Wis. Act 87, published 3-1-26) (checked 2026-10-01); 2025 Wisconsin Schedule H/H-EZ Instructions (Homestead Credit) (checked 2026-10-12); 2025 Wisconsin Schedule H, Homestead Credit Claim (checked 2026-10-12)

Rate schedule

Single

Taxable income from	to	Rate
$0	$15,110	3.5%
$15,110	$51,950	4.4%
$51,950	$332,720	5.3%
$332,720	and up	7.65%

Married filing jointly

Taxable income from	to	Rate
$0	$20,150	3.5%
$20,150	$69,260	4.4%
$69,260	$443,630	5.3%
$443,630	and up	7.65%

Head of household uses the single schedule.

Married filing separately

Taxable income from	to	Rate
$0	$10,080	3.5%
$10,080	$34,630	4.4%
$34,630	$221,820	5.3%
$221,820	and up	7.65%

2026 Form 1-ES Instructions (Wisconsin Estimated Tax Voucher Instructions), Wisconsin Department of Revenue. The 2026 Wisconsin tax rate schedules tax single/head-of-household filers at 3.5%, 4.4%, 5.3% and 7.65% with breakpoints $15,110 / $51,950 / $332,720, and married-filing-jointly filers at the same rates with breakpoints $20,150 / $69,260 / $443,630. Married filing separately has its own Schedule C: $10,080 / $34,630 / $221,820. Checked 2026-10-12.

Deductions, exemptions and credits

Standard deduction (or the exemption the engine carries in its place): $13,960 single, $25,840 married filing jointly, $18,030 head of household.
The standard deduction phases out ratably as income rises above $20,120 (single) and $29,040 (MFJ), reaching zero $116,333 and $130,650 above those points; head of household from $20,120 over $80,080; married filing separately from $13,780 over $62,089.
The head-of-household deduction never falls below the single deduction at the same income.
Married filing separately: $12,280.
Personal exemption, subtracted in addition: $700 single, $1,400 MFJ.

2026 Form 1-ES Instructions (Wisconsin Estimated Tax Voucher Instructions), Wisconsin Department of Revenue. Wisconsin's 2026 sliding-scale standard deduction is $13,960 (single) / $25,840 (MFJ), reduced by 12% (single) / 19.778% (MFJ) of Wisconsin income over $20,120 / $29,040 and reaching $0 at $136,453 / $159,690; each filer also gets a $700 personal exemption plus $250 at age 65+. Engine 1.7.0: Form 1 line 10a: $700 per dependent; Schedule SB line 22 (2440W): disability pay under 65 up to $5,200 a person, less income over $15,000; married persons must file jointly. Checked 2026-10-12.
Wisconsin Department of Revenue: 2025-Schedule2440W.pdf, Wisconsin Department of Revenue. Engine 1.7.0: Form 1 line 10a: $700 per dependent; Schedule SB line 22 (2440W): disability pay under 65 up to $5,200 a person, less income over $15,000; married persons must file jointly. Checked 2026-10-12.
Wisconsin Department of Revenue: 2025-ScheduleSB-Inst.pdf, Wisconsin Department of Revenue. Engine 1.7.0: Form 1 line 10a: $700 per dependent; Schedule SB line 22 (2440W): disability pay under 65 up to $5,200 a person, less income over $15,000; married persons must file jointly. Checked 2026-10-12.
2025 Wisconsin Form 1 Instructions, Wisconsin Department of Revenue. Engine 1.8.0 (S5): the standard deduction table (line 8) is read at line 7, Wisconsin income (federal AGI less the Schedule SB subtractions), not at federal AGI. Earned income credit (engine 1.12.0, refundableCredits): 4% / 11% / 34% of the federal EIC with 1 / 2 / 3+ qualifying children. School property tax credit (engine 1.12.0): 12% of property tax (or 20% / 25% of rent) up to $2,500, nonrefundable. Homestead credit (engine 1.12.0): Schedule H, household income under $24,680. Checked 2026-10-12.
Wis. Stat. ch. 71 (2023-24 Wis. Stats. updated through 2025 Wis. Act 87, published 3-1-26), Wisconsin Legislature (Legislative Reference Bureau). School property tax credit (engine 1.12.0): 12% of property tax (or 20% / 25% of rent) up to $2,500, nonrefundable. Homestead credit (engine 1.12.0): Schedule H, household income under $24,680. Checked 2026-10-01.
2025 Wisconsin Schedule H/H-EZ Instructions (Homestead Credit), Wisconsin Department of Revenue. Homestead credit (engine 1.12.0): Schedule H, household income under $24,680. Checked 2026-10-12.
2025 Wisconsin Schedule H, Homestead Credit Claim, Wisconsin Department of Revenue. Homestead credit (engine 1.12.0): Schedule H, household income under $24,680. Checked 2026-10-12.

Age 65+ subtractions and credits

At age 65 or older: $250 is subtracted from the base ($500 for a married couple filing jointly when both qualify), against any income. With the spouse's age given, each spouse qualifies on their own age.

2026 Form1 ES Inst, Wisconsin Department of Revenue. Wisconsin Department of Revenue: "Your exemptions are $700 for yourself, $700 for your spouse if filing a joint return, and $700 for each dependent." (and 1 more quoted passage) Checked 2026-10-12.

Social Security

Social Security benefits are fully exempt: none of the federally taxable amount enters the state base.

API value: socialSecurityRule: "exempt". The engine's input is the federally taxable amount; income tests use the sum of the income components as the adjusted-gross-income proxy.

2025 Wisconsin Schedule SB Instructions (Subtractions from Income), Wisconsin Department of Revenue. Social Security benefits are not taxable in Wisconsin; the federally taxable amount is subtracted on Schedule SB line 4. Checked 2026-10-12.
Publication 126: How Your Retirement Benefits Are Taxed, Wisconsin Department of Revenue. Wisconsin does not tax Social Security benefits. Checked 2026-10-12.

IRA, 401(k) and private pensions

Pension, annuity and IRA/401(k) distributions: up to $24,000 excluded per taxpayer ($48,000 on a joint return) at age 67 or older.
Joint returns: when both spouses pass the age test the $48,000 cap applies to their pooled income; when only one does, only that spouse's own income draws a cap.

Source review notes (what the sources do not state outright, or what the engine does not carry):

The credit-forfeiture election (claiming the subtraction bars all s.71.10(4) credits) is not modeled by the engine.

2025 Wisconsin Schedule SB Instructions (Subtractions from Income), Wisconsin Department of Revenue. A filer aged 67+ at year end may subtract up to $24,000 of federally taxable qualified-plan or IRA income ($48,000 on a joint return when both spouses are 67+, regardless of which spouse received it); claiming it forfeits all Schedule CR / Form 1 credits. Checked 2026-10-12.
Tax Practitioner Fall 2025 Questions and Answers, Wisconsin Department of Revenue. DOR guidance: the 67+ subtraction covers distributions from IRC qualified plans and IRAs, has no income limit or phase-out, and needs both spouses 67+ for the $48,000 joint amount (otherwise $24,000 limited to the 67+ spouse's own income). Checked 2026-10-12.
Publication 126: How Your Retirement Benefits Are Taxed, Wisconsin Department of Revenue. Starting in 2025, individuals 67+ may subtract up to $24,000 of qualifying retirement income ($48,000 for a joint return when both are 67+). Checked 2026-10-12.
2025 Wisconsin Schedule SB Instructions (Subtractions from Income), Wisconsin Department of Revenue. Engine 1.8.0 (S5): Schedule SB line 17 — each spouse 65 or older may subtract the IRA and qualified-plan income left after lines 12-16, up to $5,000, while federal AGI is less than $15,000 ($30,000 joint; on a separate return both spouses' combined AGI, which the engine does not have, so it gives none there). Unlike line 16 it does not forfeit the credits. Checked 2026-10-12.
2025 Wisconsin Form 1 instructions, Wisconsin Department of Revenue. A lump-sum distribution taxed on federal Form 4972 is an addition to Wisconsin income (Schedule AD) and taxed at the ordinary rates — as the engine taxes it when entered as iraDistributions; line 25 takes 33% of the federal early-distribution tax (calculated) and of the HSA and Archer MSA distribution taxes and the other plan taxes (not inputs). Checked 2026-10-12.

Public pensions

No separate treatment: public pensions follow the rules for other retirement income above.

Source review notes (what the sources do not state outright, or what the engine does not carry):

The pre-1964 membership subtraction is not modeled; the engine taxes public pensions like other pensions (eligible for the 67+ subtraction when paid from a qualified plan).

2025 Wisconsin Schedule SB Instructions (Subtractions from Income), Wisconsin Department of Revenue. Wisconsin taxes state, local and federal civil-service pensions like other pensions; only benefits from listed systems tied to membership before January 1, 1964 may be subtracted. Checked 2026-10-12.

Military retirement pay

Military retirement pay is fully exempt, at any age.
Rules are applied per taxpayer at that person's own age when the spouse's age is given. API value: rules.militaryRetirement.treatment: "exempt".

Pcs retired, Wisconsin Department of Revenue (archived copy). Military and uniformed services retirement benefits are not taxable in Wisconsin, and they do not use up the 67+ retirement subtraction. Checked 2026-09-27.

Wages

Wages are ordinary income.
Married couple credit: 3% of the lower-earning spouse's earned income, up to $480. Applied only on a joint return where each spouse's wages and the spouse's age are given.

6, Wisconsin Legislature (archived copy). Married couple credit: 3% of the lower-earning spouse's qualified earned income, at most $480; claiming the 67+ retirement subtraction forfeits all credits. Checked 2026-09-27.
Pcs retired, Wisconsin Department of Revenue (archived copy). Married couple credit: 3% of the lower-earning spouse's qualified earned income, at most $480; claiming the 67+ retirement subtraction forfeits all credits. Checked 2026-09-27.

Roth conversions

A conversion draws the retirement-income exclusion together with distributions from age 67; the part above the cap is taxed as ordinary income.

2025 Wisconsin Form 1 Instructions, Wisconsin Department of Revenue. Wisconsin income starts from federal adjusted gross income, so a traditional-to-Roth conversion included in federal AGI enters Wisconsin income. Checked 2026-10-12.
Tax Practitioner Fall 2025 Questions and Answers, Wisconsin Department of Revenue. DOR guidance: income from converting a traditional IRA to a Roth IRA is eligible for the 67+ retirement income subtraction, so the engine pools conversion income with distributions against the $24,000 / $48,000 cap at 67+. Checked 2026-10-12.

Capital gains

70% of net long-term gain enters the base (30% is excluded) and is taxed at ordinary rates.
Short-term gains are ordinary income.

Source review notes (what the sources do not state outright, or what the engine does not carry):

The 60% farm-asset exclusion is not modeled.
capitalLossCarryover is the state's own carryover; the planner passes the federal one, which understates the later years' state deduction when the state's deduction was smaller (the state tax errs high).

2025 Wisconsin Schedule WD Instructions (Capital Gains and Losses), Wisconsin Department of Revenue. Wisconsin excludes 30% of net long-term capital gain (60% for farm assets), so 70% of the gain is taxed at ordinary rates. Checked 2026-10-12.
2025 Schedule WD (Capital Gains and Losses), Wisconsin Department of Revenue. Wisconsin Schedule WD line 28 deducts the smaller of the net loss, $3,000 ($1,500 when married and not filing jointly) and Wisconsin ordinary income (engine 1.9.0: cap_loss_limit, cap_loss_ordinary_income_cap). Checked 2026-10-12.
2025 Schedule WD Instructions, Wisconsin Department of Revenue. Wisconsin Schedule WD line 28 deducts the smaller of the net loss, $3,000 ($1,500 when married and not filing jointly) and Wisconsin ordinary income (engine 1.9.0: cap_loss_limit, cap_loss_ordinary_income_cap). Checked 2026-10-12.

Blindness and disability

The API applies these through its blind, disabled, spouse.blind and spouse.disabled fields; absent means false.

Wisconsin Department of Revenue: 2026-Form1-ES-Inst.pdf, Wisconsin Department of Revenue. Engine 1.7.0: Form 1 line 10a: $700 per dependent; Schedule SB line 22 (2440W): disability pay under 65 up to $5,200 a person, less income over $15,000; married persons must file jointly. Checked 2026-10-12.
Wisconsin Department of Revenue: 2025-Schedule2440W.pdf, Wisconsin Department of Revenue. Engine 1.7.0: Form 1 line 10a: $700 per dependent; Schedule SB line 22 (2440W): disability pay under 65 up to $5,200 a person, less income over $15,000; married persons must file jointly. Checked 2026-10-12.
Wisconsin Department of Revenue: 2025-ScheduleSB-Inst.pdf, Wisconsin Department of Revenue. Engine 1.7.0: Form 1 line 10a: $700 per dependent; Schedule SB line 22 (2440W): disability pay under 65 up to $5,200 a person, less income over $15,000; married persons must file jointly. Checked 2026-10-12.

Part-year and nonresident returns

Part-year resident (Form 1NPR): the tax a full-year resident would owe on all the year's income, times the state's income ratio.
Nonresident (Form 1NPR): the tax a full-year resident would owe on all the year's income, times the state's income ratio.
The ratio: the state's own AGI (after its subtractions) of the state's income over the state AGI of the whole year, rounded to 4 places, at most 1.
The tax on the larger of Wisconsin and federal income; the 67+ retirement subtraction: barred to a nonresident, a part-year resident's maximum × the Wisconsin share of income.
A nonresident's retirement income is not taxable by the state (4 U.S.C. §114); the API refuses it in residency.stateIncome. The credit for tax paid to another state and the earned income credits on these returns are not computed.

Married couples whose residency differs (engine 1.13.0)

With residency.spouse on a joint request, each allowed treatment is calculated and reported in residency.couple; tax is the required one, else the state's default, else the couple's residency.election, else the joint return the request's mfj names. Each rule is quoted from the state's instructions (engine 1.14.0: and its statutes, regulations, bulletins and other official guidance) in the sources below.

Spouses	Wisconsin's rule
One spouse a full-year resident, the other a part-year resident	the couple's choice: a joint part-year / nonresident return or separate returns.
One spouse a full-year resident, the other a nonresident	the couple's choice: a joint part-year / nonresident return or separate returns.
One spouse a part-year resident, the other a nonresident	the couple's choice: a joint part-year / nonresident return or separate returns.
Both part-year residents, different resident periods	the couple's choice: a joint part-year / nonresident return or separate returns.
Both nonresidents, only one with income from the state	the couple's choice: a joint part-year / nonresident return or separate returns.

2025 Wisconsin Form 1NPR Instructions, Wisconsin Department of Revenue. Part-year / nonresident return (engine 1.12.0, residency): Tax is computed on the larger of Wisconsin income (line 30) or federal income (line 31), less the full standard deduction (table based on line 31 federal income) and full exemptions ($700 each, +$250 age 65); the resulting tax (line 38) is multiplied by the ratio on line 32 (line 39 'Prorated tax'). Some credits (school property tax credit) are then prorated by the same ratio. Checked 2026-10-12.
2025 Wisconsin Form 1NPR, Wisconsin Department of Revenue. Part-year / nonresident return (engine 1.12.0, residency): Tax is computed on the larger of Wisconsin income (line 30) or federal income (line 31), less the full standard deduction (table based on line 31 federal income) and full exemptions ($700 each, +$250 age 65); the resulting tax (line 38) is multiplied by the ratio on line 32 (line 39 'Prorated tax'). Some credits (school property tax credit) are then prorated by the same ratio. Checked 2026-10-12.
2025 Wisconsin Schedule M Instructions, Wisconsin Department of Revenue. Part-year / nonresident return (engine 1.12.0, residency): Tax is computed on the larger of Wisconsin income (line 30) or federal income (line 31), less the full standard deduction (table based on line 31 federal income) and full exemptions ($700 each, +$250 age 65); the resulting tax (line 38) is multiplied by the ratio on line 32 (line 39 'Prorated tax'). Some credits (school property tax credit) are then prorated by the same ratio. Checked 2026-10-12.
2025 Form 1NPR Instructions: Nonresident and Part-Year Resident Individual Income Tax Return, Wisconsin Department of Revenue. Married couples whose residency differs (engine 1.13.0): Checked 2026-10-12.

Worked examples

Computed by the engine for the fixed households below (the same ones for every state, so states compare directly). Federal tax is not supplied, so a federal-tax deduction is not taken; the income tests use the sum of the components as income.

Household (engine inputs)	State tax
Single, 67: $30,000 private pension, $20,000 IRA, $10,000 interest, $24,000 Social Security ($17,000 federally taxable), $5,000 long-term gain	$1,048.30
Married filing jointly, 70: $40,000 public pension, $40,000 IRA, $20,000 interest, $40,000 Social Security ($34,000 federally taxable), $10,000 long-term gain	$1,454.81
Single, 60: $60,000 other ordinary income and a $50,000 Roth conversion	$5,021.12
Married filing jointly, 66: $30,000 IRA, a $40,000 Roth conversion, $30,000 Social Security ($25,500 federally taxable)	$2,034.54
Single, 58: $36,000 military retirement pay and $30,000 wages	$591.14
Married filing jointly, ages 67 and 61: $50,000 IRA, $10,000 interest, $30,000 Social Security ($25,500 federally taxable), each spouse's age given	$346.03

Line by line

The intermediate lines the engine records while it computes each example (its detail record, printed as it comes out; lines that are zero are left out). The engine's documentation build checks that the lines add up to the taxable income and the tax, for every state, filing status and a grid of households. Each line links the engine step that produces it.

Single, 67: $30,000 private pension, $20,000 IRA, $10,000 interest, $24,000 Social Security ($17,000 federally taxable), $5,000 long-term gain: $1,048.30

Line	Amount
Income total used by the income tests	$82,000
Retirement income and conversions excluded (not in the base)	$24,000
+ Other ordinary income in the base	$10,000
+ Retirement income in the base	$26,000
+ Long-term gain in the base	$3,500
− Standard deduction	$11,634.39
− Personal exemption	$700
− Age subtractions and deductions	$250
= State taxable income	$26,915.61
Tax from the rate schedule	$1,048.30
= Tax before credits	$1,048.30
= Tax	$1,048.30

Married filing jointly, 70: $40,000 public pension, $40,000 IRA, $20,000 interest, $40,000 Social Security ($34,000 federally taxable), $10,000 long-term gain: $1,454.81

Line	Amount
Income total used by the income tests	$144,000
Retirement income and conversions excluded (not in the base)	$48,000
+ Other ordinary income in the base	$20,000
+ Retirement income in the base	$32,000
+ Long-term gain in the base	$7,000
− Standard deduction	$19,914.50
− Personal exemption	$1,400
− Age subtractions and deductions	$500
= State taxable income	$37,185.50
Tax from the rate schedule	$1,454.81
= Tax before credits	$1,454.81
= Tax	$1,454.81

Single, 60: $60,000 other ordinary income and a $50,000 Roth conversion: $5,021.12

Line	Amount
Income total used by the income tests	$110,000
+ Other ordinary income in the base	$60,000
+ Roth conversion in the base	$50,000
− Standard deduction	$3,174.37
− Personal exemption	$700
= State taxable income	$106,125.63
Tax from the rate schedule	$5,021.12
= Tax before credits	$5,021.12
= Tax	$5,021.12

Married filing jointly, 66: $30,000 IRA, a $40,000 Roth conversion, $30,000 Social Security ($25,500 federally taxable): $2,034.54

Line	Amount
Income total used by the income tests	$95,500
+ Retirement income in the base	$30,000
+ Roth conversion in the base	$40,000
− Standard deduction	$17,738.92
− Personal exemption	$1,400
− Age subtractions and deductions	$500
= State taxable income	$50,361.08
Tax from the rate schedule	$2,034.54
= Tax before credits	$2,034.54
= Tax	$2,034.54

Single, 58: $36,000 military retirement pay and $30,000 wages: $591.14

Line	Amount
Income total used by the income tests	$66,000
Military pay excluded (not in the base)	$36,000
+ Other ordinary income in the base	$30,000
− Standard deduction	$12,774.40
− Personal exemption	$700
= State taxable income	$16,525.60
Tax from the rate schedule	$591.14
= Tax before credits	$591.14
= Tax	$591.14

Married filing jointly, ages 67 and 61: $50,000 IRA, $10,000 interest, $30,000 Social Security ($25,500 federally taxable), each spouse's age given: $346.03

Line	Amount
Income total used by the income tests	$85,500
Retirement income and conversions excluded (not in the base)	$24,000
+ Other ordinary income in the base	$10,000
+ Retirement income in the base	$26,000
− Standard deduction	$24,463.45
− Personal exemption	$1,400
− Age subtractions and deductions	$250
= State taxable income	$9,886.55
Tax from the rate schedule	$346.03
= Tax before credits	$346.03
= Tax	$346.03

After 2026: how the amounts move

A request with projection (API) estimates a later tax year from these rules: every dollar amount and age test below moves the way Wisconsin's law moves it. Rates and the rules themselves stay the 2026 ones (how projection works).

Amounts (engine fields)	After 2026	What the law says, and the source
`brackets_single` (the single rate schedule's thresholds), `brackets_mfj` (the mfj rate schedule's thresholds), `brackets_mfs` (the mfs rate schedule's thresholds)	Indexed: CPI-U (U.S. city average), August of the previous year vs. the base August; no decrease year over year (August 2024 base); the increase rounded to the nearest $10.	For tax years after 2025 the bracket amounts in subs. (1r), (2)(k) and (L) are increased each year by the CPI-U change from August 2024 to August of the previous year, only if the result exceeds the prior year's amount, rounded to the nearest $10 ($5 rounds up). Wis. Stat. § 71.06(2e) (Wayback capture of docs.legis.wisconsin.gov) (Wisconsin Legislature (Legislative Reference Bureau), statute): Bracket indexing for 2026+ (CPI-U, August 2024 base, no decreases, nearest $10). Quoted: "shall be increased each year by a percentage equal to the percentage change between the U.S. consumer price index for all urban consumers, U.S. city average, for the month of August of the previous year and the U.S. consumer price index for all urban consumers, U.S. city average, for the month of August 2024"; "Each amount that is revised under this subsection shall be rounded to the nearest multiple of $10". Checked 2026-09-30.
`std_deduction_single`, `std_deduction_mfj`, `std_deduction_hoh`, `std_deduction_mfs`, `std_deduction_phaseout_start_single`, `std_deduction_phaseout_start_mfj`, `std_deduction_phaseout_start_hoh`, `std_deduction_phaseout_start_mfs`, `std_deduction_phaseout_denom_single`, `std_deduction_phaseout_denom_mfj`, `std_deduction_phaseout_denom_hoh`, `std_deduction_phaseout_denom_mfs`	Indexed: CPI-U (U.S. city average), August of the previous year vs. the base August; no decrease year over year (August 1999 base; 2015 for joint/MFS); the increase rounded to the nearest $10.	The sliding-scale standard deduction amounts and all its AGI amounts are increased each year by CPI-U (August 1999 base; 2015 base for the joint/MFS amounts), never downward, rounded to the nearest $10. The phase-out rates (12%, 19.778%, 22.515%) are fixed, so the phase-out widths (deduction / rate) scale with the indexed deduction. Wis. Stat. § 71.05(22)-(23) (Wayback capture of docs.legis.wisconsin.gov) (Wisconsin Legislature (Legislative Reference Bureau), statute): Standard deduction indexing (par. (dt)) and personal exemptions (sub. (23)). Quoted: "the dollar amounts of the standard deduction that is allowable under par. (dp) and all of the dollar amounts of Wisconsin adjusted gross income under par. (dp) shall be increased each year"; "Each amount that is revised under this paragraph shall be rounded to the nearest multiple of $10". Checked 2026-10-12.
`personal_exemption_single`, `personal_exemption_mfj`, `dep_exemption`, `senior_subtraction_single`, `senior_subtraction_mfj`	Fixed in law: held at the rules-year amount in every later year.	The $700 personal/dependent exemptions and the additional $250 for age 65+ are nominal in § 71.05(23)(b); no inflation adjustment. Wis. Stat. § 71.05(22)-(23) (Wayback capture of docs.legis.wisconsin.gov) (Wisconsin Legislature (Legislative Reference Bureau), statute): Standard deduction indexing (par. (dt)) and personal exemptions (sub. (23)). Quoted: "A personal exemption of $700 if the taxpayer is required to file a return"; "An exemption of $700 for each dependent"; "An additional exemption of $250 if the taxpayer has reached the age of 65". Checked 2026-10-12.
`senior_subtraction_min_age`	Attained age: the same age in every year.	Fixed attained age: 65 before the close of the taxable year. Wis. Stat. § 71.05(22)-(23) (Wayback capture of docs.legis.wisconsin.gov) (Wisconsin Legislature (Legislative Reference Bureau), statute): Standard deduction indexing (par. (dt)) and personal exemptions (sub. (23)). Quoted: "has reached the age of 65 before the close of the taxable year". Checked 2026-10-12.
`retirement_income_exclusion_single`, `retirement_income_exclusion_mfj`	Fixed in law: held at the rules-year amount in every later year.	For tax years after 2024, retirement plan/IRA distributions of an individual 67+ are subtracted up to $24,000 ($48,000 for a joint couple both 67+); nominal, no inflation adjustment in subd. 54m. Wis. Stat. § 71.05(6)(b)54. and 54m. (Wayback capture of docs.legis.wisconsin.gov) (Wisconsin Legislature (Legislative Reference Bureau), statute): Retirement income subtractions. Quoted: "may claim the subtraction under this subdivision in an amount not to exceed $24,000 for the taxable year"; "may not exceed $48,000 for that taxable year". Checked 2026-10-12.
`retirement_exclusion_min_age`, `conversion_exclusion_min_age`	Attained age: the same age in every year.	Fixed attained age: at least 67 before the close of the taxable year (applies to every distribution the subtraction covers, including a conversion). Wis. Stat. § 71.05(6)(b)54. and 54m. (Wayback capture of docs.legis.wisconsin.gov) (Wisconsin Legislature (Legislative Reference Bureau), statute): Retirement income subtractions. Quoted: "If the individual is at least 67 years of age before the close of the taxable year to which the subtraction relates". Checked 2026-10-12.
`lowinc_ret_subtraction`, `lowinc_ret_subtraction_agi_single`, `lowinc_ret_subtraction_agi_mfj`	Fixed in law: held at the rules-year amount in every later year.	Up to $5,000 of retirement distributions for a 65+ individual with federal AGI under $15,000 (single/HOH) or $30,000 (joint); nominal in subd. 54, no inflation adjustment. Wis. Stat. § 71.05(6)(b)54. and 54m. (Wayback capture of docs.legis.wisconsin.gov) (Wisconsin Legislature (Legislative Reference Bureau), statute): Retirement income subtractions. Quoted: "up to $5,000 of payments or distributions received each year by an individual"; "his or her federal adjusted gross income in the year to which the exemption claim relates is less than $15,000"; "the couple's federal adjusted gross income in the year to which the exemption claim relates is less than $30,000". Checked 2026-10-12.
`lowinc_ret_subtraction_min_age`	Attained age: the same age in every year.	Fixed attained age 65. Wis. Stat. § 71.05(6)(b)54. and 54m. (Wayback capture of docs.legis.wisconsin.gov) (Wisconsin Legislature (Legislative Reference Bureau), statute): Retirement income subtractions. Quoted: "The individual is at least 65 years of age before the close of the taxable year". Checked 2026-10-12.
`dis_income_cap`, `dis_income_reduce_over`	Fixed in law: held at the rules-year amount in every later year.	Disability pay exclusion of $100 per week (= $5,200 a year), reduced dollar for dollar by federal AGI over $15,000; nominal in subd. 4., no inflation adjustment. Wis. Stat. § 71.05(6)(b)4. (Wayback capture of docs.legis.wisconsin.gov) (Wisconsin Legislature (Legislative Reference Bureau), statute): Disability income subtraction. Quoted: "the maximum subtraction is $100 for each week that payments are received"; "shall be reduced by an amount equal to the excess of the federal adjusted gross income over $15,000". Checked 2026-09-30.
`dis_income_max_age`	Attained age: the same age in every year.	Only for an individual under 65 before the close of the taxable year (fixed age). Wis. Stat. § 71.05(6)(b)4. (Wayback capture of docs.legis.wisconsin.gov) (Wisconsin Legislature (Legislative Reference Bureau), statute): Age limit. Quoted: "is under 65 years of age before the close of the taxable year". Checked 2026-09-30.
`married_couple_credit_max`	Fixed in law: held at the rules-year amount in every later year.	3% of the lower earner's qualified earned income, capped at $480, for tax years after 2000; nominal, no adjustment. Wis. Stat. § 71.07(6)(am)2.d. (Wayback capture of docs.legis.wisconsin.gov) (Wisconsin Legislature (Legislative Reference Bureau), statute): Married persons credit. Quoted: "3 percent of the qualified earned income of the spouse with the lower qualified earned income, but not more than $480". Checked 2026-09-30.
`cap_loss_limit`, `cap_loss_limit_mfs`	Fixed in law: held at the rules-year amount in every later year.	Wisconsin applies the federal IRC 1211(b) limit, fixed in federal law. 26 U.S.C. 1211 (Limitation on capital losses) (Legal Information Institute (Cornell) - U.S. Code, federal): IRC 1211(b) limits a non-corporate capital loss against other income to $3,000 ($1,500 MFS), with no inflation adjustment. Quoted: "(1) $3,000 ($1,500 in the case of a married individual filing a separate return), or". Checked 2026-10-12.
`school_ptc_base_cap`	Fixed in law: held at the rules-year amount in every later year.	Wis. Stat. 71.07(9): 12 percent of the first $2,500 ($1,250 married filing separately) of property taxes or rent constituting property taxes; fixed since tax year 2000. Wis. Stat. chapter 71 (Internet Archive copy) (Wisconsin Legislature, statute): 71.07(9). Quoted: "12 percent of the first $2,500 of property taxes or rent constituting property taxes". Checked 2026-10-12.
`wi-homestead-credit` (a table held in code)	Fixed in law: held at the rules-year amount in every later year.	Wis. Stat. 71.54(1)(g) and (2)(b)4.: the $8,060 threshold, 8.785%, $1,460 and $24,680 apply to 2012 and later years: fixed. Wis. Stat. ch. 71 (2023-24 Wis. Stats. updated through 2025 Wis. Act 87, published 3-1-26) (Wisconsin Legislature (Legislative Reference Bureau), statute): Wisconsin Homestead Credit (Wis. Stat. 71.52-71.54; Schedule H) - exact formula, 2025 and 2026 Quoted: "If the household income was $8,060 or less in the year to which the claim relates"; "exceeds 8.785 percent of the household income exceeding $8,060". Checked 2026-10-12. 2025 Wisconsin Schedule H, Homestead Credit Claim (Wisconsin Department of Revenue, instructions): Wisconsin Homestead Credit (Wis. Stat. 71.52-71.54; Schedule H) - exact formula, 2025 and 2026 Quoted: "Fill in the smaller of (a) amount on line 15 or (b) $1,460"; "Using the amount on line 12c, fill in the appropriate amount from Table A (page 25)". Checked 2026-10-12.

Enacted for later years, not applied by the projection

None found: the research found no change enacted for years after 2026 beyond the schedules above.

What the engine does not calculate, and known approximations

The Schedule SB line 17 subtraction is not given on a separate return (its limit is both spouses' combined federal AGI, which is not an input), and Roth conversions, which the federal return reports with IRA distributions, are not counted toward it.
The credit-forfeiture election (claiming the subtraction bars all s.71.10(4) credits) is not modeled by the engine. (IRA, 401(k) and private pensions)
The pre-1964 membership subtraction is not modeled; the engine taxes public pensions like other pensions (eligible for the 67+ subtraction when paid from a qualified plan). (Public pensions)
The 60% farm-asset exclusion is not modeled. (Capital gains)
The additional child and dependent care credit needs expenses and is not calculated. Sources: 2026 Form 1-ES Instructions (Wisconsin Estimated Tax Voucher Instructions) (checked 2026-10-12); Wisconsin Department of Revenue: 2025-Schedule2440W.pdf (checked 2026-10-12); Wisconsin Department of Revenue: 2025-ScheduleSB-Inst.pdf (checked 2026-10-12); 2025 Wisconsin Form 1 Instructions (checked 2026-10-12); Wis. Stat. ch. 71 (2023-24 Wis. Stats. updated through 2025 Wis. Act 87, published 3-1-26) (checked 2026-10-01); 2025 Wisconsin Schedule H/H-EZ Instructions (Homestead Credit) (checked 2026-10-12); 2025 Wisconsin Schedule H, Homestead Credit Claim (checked 2026-10-12).
The medical care insurance and long-term care insurance subtractions (Schedule SB lines 6 and 7, including Medicare premiums withheld from Social Security) need the premiums paid and are not calculated. Sources: 2026 Form 1-ES Instructions (Wisconsin Estimated Tax Voucher Instructions) (checked 2026-10-12); Wisconsin Department of Revenue: 2025-Schedule2440W.pdf (checked 2026-10-12); Wisconsin Department of Revenue: 2025-ScheduleSB-Inst.pdf (checked 2026-10-12); 2025 Wisconsin Form 1 Instructions (checked 2026-10-12); Wis. Stat. ch. 71 (2023-24 Wis. Stats. updated through 2025 Wis. Act 87, published 3-1-26) (checked 2026-10-01); 2025 Wisconsin Schedule H/H-EZ Instructions (Homestead Credit) (checked 2026-10-12); 2025 Wisconsin Schedule H, Homestead Credit Claim (checked 2026-10-12).
Wisconsin's penalty on IRAs, retirement plans and MSAs (Form 1 line 25, its share of the federal taxes) is calculated only for the federal additional tax on early IRA and employer-plan distributions; its share of the federal taxes on HSA and Archer MSA distributions, excess contributions, prohibited transactions and section 72(m)(5) excess benefits is not: the inputs do not carry them. (A lump-sum distribution taxed on federal Form 4972 is added back to Wisconsin income and taxed at the ordinary rates, as the engine taxes it when entered as iraDistributions.) Sources: 2025 Wisconsin Schedule SB Instructions (Subtractions from Income) (checked 2026-10-12); Tax Practitioner Fall 2025 Questions and Answers (checked 2026-10-12); Publication 126: How Your Retirement Benefits Are Taxed (checked 2026-10-12); 2025 Wisconsin Schedule SB Instructions (Subtractions from Income) (checked 2026-10-12); 2025 Wisconsin Form 1 instructions (checked 2026-10-12).

What the engine does not calculate for any state (itemized deductions, credits beyond those listed, part-year residents, and more) is listed on the calculation order page.

Verification

Worksheet-tested Engine 1.2.0 tests follow the 2026 Form 1-ES standard-deduction table, including the head-of-household and MFS rows; engine 1.8.0 (S5) tests read it at Form 1 line 7 and replay Schedule SB line 17.

Golden scenarios (hand-computed expected tax, asserted to within $1): WI90, WI91, WI92.
State-specific unit tests: test_block_zero_is_170, test_c_interface_edges, test_wi_hoh_floor_and_me_mfs_exemption, test_v4_equals_detail, test_wi_married_couple_credit, test_wi, test_worked_ratios, test_ratio_rules, test_engine_paths, test_wi_2026_deductions_exemptions, test_wi_mfs_schedule_c.
Structural tests covering every state: 9.
State forms and worksheets followed in the test derivations: Form 1-ES (2026) standard deduction table; Form 1 line 7 / line 8 (2025 instructions); Schedule SB line 17 Retirement Income Subtraction Worksheet (2025).