State tax docs / States / Ohio

Ohio state income tax: engine rules, 2026

How the QuantCalc engine computes Ohio 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 · 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 OH).

How the tax is computed

Every step the engine takes for Ohio, 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 Ohio'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	single schedule	single schedule
Top rate	2.75% from $26,050	2.75% from $26,050	2.75% from $26,050	2.75% from $26,050
Standard deduction, under 65	none	none	none	none
Standard deduction at 70 (joint: both 70)	none	none	none	none
Personal exemption	$2,400	$4,800	$2,400	$2,400
Age subtractions at 70 (joint: both 70)	none	none	none	none

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.
Ohio's values · engine step (select_brackets). Sources (Rate schedule): Annual Tax Rates (checked 2026-10-12); 2025 Ohio IT 1040 / SD 100 Instructions (checked 2026-10-12); Section 5747.02 (checked 2026-09-28); Section 5747.025 (checked 2026-09-28)
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).
Ohio's values · engine step (select_brackets). Sources (Rate schedule): Annual Tax Rates (checked 2026-10-12); 2025 Ohio IT 1040 / SD 100 Instructions (checked 2026-10-12); Section 5747.02 (checked 2026-09-28); Section 5747.025 (checked 2026-09-28)
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.
Ohio's values · engine step (select_brackets). Sources (Rate schedule): Annual Tax Rates (checked 2026-10-12); 2025 Ohio IT 1040 / SD 100 Instructions (checked 2026-10-12); Section 5747.02 (checked 2026-09-28); Section 5747.025 (checked 2026-09-28)
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.
The plan's minimum retirement age 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) Where the state reads it, the minimum retirement age of the plan paying a person's disability pay (the filer's, or the spouse's on a joint return), when given: from that age the pay is a pension. Not given, each state keeps its own reading.
Ohio's values · engine step (dis_plan_age). Sources (IRA, 401(k) and private pensions): 2025 Ohio IT 1040 / SD 100 Instructions (checked 2026-10-12); Publication 525 (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.
Ohio's values · engine step (compute_state_tax_detail). Sources (Blindness and disability): Ohio Department of Taxation: it1040-booklet.pdf (checked 2026-10-12); Ohio Legislature (Ohio Revised Code): section-5747.025 (checked 2026-09-28); Ohio Legislature (Ohio Revised Code): section-5747.055 (checked 2026-09-28); Ohio Department of Taxation: scheduleofcredits.pdf (checked 2026-10-12); Ohio Legislature (Ohio Revised Code): section-5747.01 (checked 2026-09-28)
Survivor benefits 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) A survivor's retirement income (the caller's survivorBenefits: the person's pension and IRA income is received as a beneficiary; without a spouse object the fact describes the household). Where the state deducts survivor benefits, the pension part leaves the base before Ohio-style income tests (the IRA part stays: an inherited account was payable without the death). Where the state gives a surviving spouse its own deduction, up to the state's amount of that income is deducted and the rest gets no own-plan retirement deduction (it is not the survivor's own plan) and is taxed as ordinary income; military pay keeps the military rule. The surviving-spouse deduction is the higher amount when the deceased spouse would have reached the state's age (the deceased spouse's age, when given).
Ohio's values · engine step (compute_state_tax_detail). Sources (IRA, 401(k) and private pensions): 2025 Ohio IT 1040 / SD 100 Instructions (checked 2026-10-12); Publication 525 (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.
Ohio's values · engine step (compute_state_tax_detail). Sources (Military retirement pay): Military (checked 2026-10-12)
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.
Ohio's values · engine step (military_exempt_one). Sources (Military retirement pay): Military (checked 2026-10-12)
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).
Ohio's values · engine step (compute_state_tax_detail). Sources (Capital gains): 2025 Ohio IT 1040 / SD 100 Instructions (checked 2026-10-12); Ohio Revised Code §5747.01 (archived) (checked 2026-09-28); 2025 Schedule D (Form 1040), Capital Gains and Losses (checked 2026-10-12)
Social Security exempt None of the federally taxable benefit enters the base.
Ohio's values · engine step (ss_amount_in_state_base). Sources (Social Security): 2025 Ohio IT 1040 / SD 100 Instructions (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.
Ohio's values · engine step (compute_state_tax_detail). Sources (IRA, 401(k) and private pensions): 2025 Ohio IT 1040 / SD 100 Instructions (checked 2026-10-12); Publication 525 (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.
Ohio's values · engine step (compute_state_tax_detail). Sources (Roth conversions): 2025 Ohio IT 1040 / SD 100 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.
Ohio's values · engine step (compute_state_tax_detail). Sources (Capital gains): 2025 Ohio IT 1040 / SD 100 Instructions (checked 2026-10-12); Ohio Revised Code §5747.01 (archived) (checked 2026-09-28); 2025 Schedule D (Form 1040), Capital Gains and Losses (checked 2026-10-12)
Exemption set by income The amount per exemption is the first tier whose income limit the income total does not exceed (joint limits for joint returns, and for head of household where set), else the amount above the tiers; two exemptions on a joint return, one otherwise. It replaces the flat exemption.
Ohio's values · engine step (compute_state_tax_detail). Sources (Deductions, exemptions and credits): 2025 Ohio IT 1040 / SD 100 Instructions (checked 2026-10-12); Section 5747.02 (checked 2026-09-28); Section 5747.025 (checked 2026-09-28); 2025 Ohio IT 1040 / SD 100 Instructions (checked 2026-10-12); Ohio Legislature (Ohio Revised Code): section-5747.055 (checked 2026-09-28); Ohio Department of Taxation: scheduleofcredits.pdf (checked 2026-10-12); Ohio Legislature (Ohio Revised Code): section-5747.01 (checked 2026-09-28)
Exemption tiers on the state's own income The tiers (and the joint filing credit's income limit) test the state base before exemptions, with the Social Security and military pay the state deducts already out, instead of the federal-style income total.
Ohio's values · engine step (compute_state_tax_detail). Sources (Deductions, exemptions and credits): 2025 Ohio IT 1040 / SD 100 Instructions (checked 2026-10-12); Section 5747.02 (checked 2026-09-28); Section 5747.025 (checked 2026-09-28); 2025 Ohio IT 1040 / SD 100 Instructions (checked 2026-10-12); Ohio Legislature (Ohio Revised Code): section-5747.055 (checked 2026-09-28); Ohio Department of Taxation: scheduleofcredits.pdf (checked 2026-10-12); Ohio Legislature (Ohio Revised Code): section-5747.01 (checked 2026-09-28)
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).
Ohio's values · engine step (compute_state_tax_detail). Sources (Deductions, exemptions and credits): 2025 Ohio IT 1040 / SD 100 Instructions (checked 2026-10-12); Section 5747.02 (checked 2026-09-28); Section 5747.025 (checked 2026-09-28); 2025 Ohio IT 1040 / SD 100 Instructions (checked 2026-10-12); Ohio Legislature (Ohio Revised Code): section-5747.055 (checked 2026-09-28); Ohio Department of Taxation: scheduleofcredits.pdf (checked 2026-10-12); Ohio Legislature (Ohio Revised Code): section-5747.01 (checked 2026-09-28)
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.
Ohio's values · engine step (compute_state_tax_detail). Sources (Rate schedule): Annual Tax Rates (checked 2026-10-12); 2025 Ohio IT 1040 / SD 100 Instructions (checked 2026-10-12); Section 5747.02 (checked 2026-09-28); Section 5747.025 (checked 2026-09-28)
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.
Ohio's values · engine step (apply_state_brackets). Sources (Rate schedule): Annual Tax Rates (checked 2026-10-12); 2025 Ohio IT 1040 / SD 100 Instructions (checked 2026-10-12); Section 5747.02 (checked 2026-09-28); Section 5747.025 (checked 2026-09-28)
Fixed amount above the zero bracket Once taxable income passes the threshold a fixed amount is added (halved with the schedule for a separate return).
Ohio's values · engine step (compute_state_tax_detail). Sources (Rate schedule): Annual Tax Rates (checked 2026-10-12); 2025 Ohio IT 1040 / SD 100 Instructions (checked 2026-10-12); Section 5747.02 (checked 2026-09-28); Section 5747.025 (checked 2026-09-28)
Retiree credits The retirement income credit by the retirement income left in the base (one per return) and a senior credit per return, both while income less exemptions is under the limit; the retirement income credit on the pension income of the persons at the age, at most the base less all Social Security and less household income over the household base; and the senior head of household credit on taxable income, at most the cap, for a filer at the age whose head-of-household qualifying person died in one of the two previous years, while income is at most the limit.
engine step (compute_state_tax_detail). Sources: Ohio Department of Taxation: it1040-booklet.pdf (checked 2026-10-12); Ohio Legislature (Ohio Revised Code): section-5747.025 (checked 2026-09-28); Ohio Legislature (Ohio Revised Code): section-5747.055 (checked 2026-09-28); Ohio Department of Taxation: scheduleofcredits.pdf (checked 2026-10-12); Ohio Legislature (Ohio Revised Code): section-5747.01 (checked 2026-09-28)
Low-income exemption credit A credit per exemption (one, two on a joint return) while taxable income, the income less exemptions, is below the limit.
Ohio's values · engine step (compute_state_tax_detail). Sources (Deductions, exemptions and credits): 2025 Ohio IT 1040 / SD 100 Instructions (checked 2026-10-12); Section 5747.02 (checked 2026-09-28); Section 5747.025 (checked 2026-09-28); 2025 Ohio IT 1040 / SD 100 Instructions (checked 2026-10-12); Ohio Legislature (Ohio Revised Code): section-5747.055 (checked 2026-09-28); Ohio Department of Taxation: scheduleofcredits.pdf (checked 2026-10-12); Ohio Legislature (Ohio Revised Code): section-5747.01 (checked 2026-09-28)
Joint filing credit joint returns with each spouse's own amounts given Joint returns with the spouse's age and a spouse split only, income under $500,000 (the state's own income where it tests that), and each spouse with at least $500 of wages, retirement or conversion income: a share, by taxable income, 15% from the first dollar of tax; 10% over $50,000; 5% over $75,000, of the tax (after the credits before it, where the state says so), at most $650.
Ohio's values · engine step (compute_state_tax_detail). Sources (Wages): It1040 booklet (checked 2026-10-12); Ohio Revised Code 5747.05 (Internet Archive copy) (checked 2026-09-28)
The federal earned income credit The federal earned income credit the state credits read: the credit rate on earned income up to the maximum, less the phase-out rate on the larger of the income total and earned income over the start (joint start on a joint return) — where the state says so, measured from the income at which the maximum is reached when that is higher; none above the investment-income limit; by qualifying children (dependents under 19, students under 24, disabled at any age; at most 3); without one the filer or a spouse must be at least the minimum age where the state sets one and under the maximum age. Not on a separate return.
Ohio's values · engine step (federal_eic). Sources (Deductions, exemptions and credits): 2025 Ohio IT 1040 / SD 100 Instructions (checked 2026-10-12); Section 5747.02 (checked 2026-09-28); Section 5747.025 (checked 2026-09-28); 2025 Ohio IT 1040 / SD 100 Instructions (checked 2026-10-12); Ohio Legislature (Ohio Revised Code): section-5747.055 (checked 2026-09-28); Ohio Department of Taxation: scheduleofcredits.pdf (checked 2026-10-12); Ohio Legislature (Ohio Revised Code): section-5747.01 (checked 2026-09-28)
State earned income credit as a share of the federal credit Where the state's credit is simply a share of the federal earned income credit (the step above), that share, nonrefundable, after the other credits the form takes first.
Ohio's values · engine step (compute_state_tax_detail). Sources (Deductions, exemptions and credits): 2025 Ohio IT 1040 / SD 100 Instructions (checked 2026-10-12); Section 5747.02 (checked 2026-09-28); Section 5747.025 (checked 2026-09-28); 2025 Ohio IT 1040 / SD 100 Instructions (checked 2026-10-12); Ohio Legislature (Ohio Revised Code): section-5747.055 (checked 2026-09-28); Ohio Department of Taxation: scheduleofcredits.pdf (checked 2026-10-12); Ohio Legislature (Ohio Revised Code): section-5747.01 (checked 2026-09-28)
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).
Ohio's values · engine step (state_tax_effective_config). Sources (Rate schedule): Annual Tax Rates (checked 2026-10-12); 2025 Ohio IT 1040 / SD 100 Instructions (checked 2026-10-12); Section 5747.02 (checked 2026-09-28); Section 5747.025 (checked 2026-09-28)
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.
Ohio's values · engine step (compute_state_tax_detail). Sources (Social Security): 2025 Ohio IT 1040 / SD 100 Instructions (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.
Ohio's values · engine step (compute_state_tax_detail). Sources (Capital gains): 2025 Ohio IT 1040 / SD 100 Instructions (checked 2026-10-12); Ohio Revised Code §5747.01 (archived) (checked 2026-09-28); 2025 Schedule D (Form 1040), Capital Gains and Losses (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).
Ohio's values · engine step (compute_state_tax_detail). Sources (Social Security): 2025 Ohio IT 1040 / SD 100 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).
Ohio's values · engine step (state_tax_refundable_credits). Sources (Deductions, exemptions and credits): 2025 Ohio IT 1040 / SD 100 Instructions (checked 2026-10-12); Section 5747.02 (checked 2026-09-28); Section 5747.025 (checked 2026-09-28); 2025 Ohio IT 1040 / SD 100 Instructions (checked 2026-10-12); Ohio Legislature (Ohio Revised Code): section-5747.055 (checked 2026-09-28); Ohio Department of Taxation: scheduleofcredits.pdf (checked 2026-10-12); Ohio Legislature (Ohio Revised Code): section-5747.01 (checked 2026-09-28)

Rate schedule

0% on the first $26,050 of state taxable income, then 2.75% above it, for every filing status.

Head of household uses the single schedule.

A fixed $332 is owed once taxable income exceeds $26,050, on top of the rate on the excess.

Married filing separately: one schedule applies to every filing status, so the engine uses it unscaled with the single deduction.

Annual Tax Rates, Ohio Department of Taxation. For 2025, Ohio taxes the first $26,050 of taxable nonbusiness income at 0% and income from $26,050 to $100,000 at $342 plus 2.75% of the excess; the page does not yet list a 2026 schedule. Checked 2026-10-12.
2025 Ohio IT 1040 / SD 100 Instructions, Ohio Department of Taxation. The 2025 Ohio income tax brackets apply one schedule to all filing statuses: 0% up to $26,050, then $342.00 plus 2.750% of the excess over $26,050 up to $100,000, then $2,394.32 plus 3.125% above $100,000. Checked 2026-10-12.
State Individual Income Tax Rates and Brackets, 2026, Tax Foundation (secondary). Tax Foundation lists Ohio for 2026 at 2.75% over $26,050 for both single and joint filers, with a $2,400 personal exemption. Checked 2026-10-12.
Section 5747.02, codes.ohio.gov (archived copy). codes.ohio.gov: "(c) for taxable years beginning in 2026 and thereafter, $332.00 plus 2.75% of the amount in excess of $26,050" Checked 2026-09-28.
Section 5747.025, codes.ohio.gov (archived copy). codes.ohio.gov: "five hundred thousand dollars for taxable years beginning in 2026 or thereafter" Checked 2026-09-28.

Deductions, exemptions and credits

No standard deduction.
Personal exemption per exemption (one single, two joint), set by income: $2,400 up to $40,000 of income; $2,150 up to $80,000 of income; $1,900 below $500,000 of income; $0 above.

2025 Ohio IT 1040 / SD 100 Instructions, Ohio Department of Taxation. Ohio has no standard deduction; the personal and dependent exemption is $2,400 per exemption for MAGI of $40,000 or less, $2,150 for $40,001-$80,000, $1,900 for $80,001-$749,999 and $0 at $750,000 or more (2025). Engine 1.7.0: IT 1040 line 4: each dependent gets the filer's stepped exemption amount; the Schedule of Credits retirement income credit (one per return, by the retirement income in Ohio AGI: $25 over $500 up to $200 over $8,000) and the $50 senior credit (per return, filer or spouse 65+), both while MAGI less exemptions is under $100,000, come before the joint filing credit; R.C. 5747.01(A)(4): disability benefits are deducted in full. Checked 2026-10-12.
Section 5747.02, codes.ohio.gov (archived copy). codes.ohio.gov: "(c) for taxable years beginning in 2026 and thereafter, $332.00 plus 2.75% of the amount in excess of $26,050" Checked 2026-09-28.
Section 5747.025, codes.ohio.gov (archived copy). codes.ohio.gov: "five hundred thousand dollars for taxable years beginning in 2026 or thereafter" Engine 1.7.0: IT 1040 line 4: each dependent gets the filer's stepped exemption amount; the Schedule of Credits retirement income credit (one per return, by the retirement income in Ohio AGI: $25 over $500 up to $200 over $8,000) and the $50 senior credit (per return, filer or spouse 65+), both while MAGI less exemptions is under $100,000, come before the joint filing credit; R.C. 5747.01(A)(4): disability benefits are deducted in full. Checked 2026-09-28.
2025 Ohio IT 1040 / SD 100 Instructions, Ohio Department of Taxation. The exemption amount, the exemption credit and the joint filing credit are based on MAGI, which is Ohio AGI (after the deductions for taxable Social Security and uniformed-services retirement pay) plus any business income deduction. The exemption credit is $20 per exemption when MAGI less exemptions is under $30,000. Checked 2026-10-12.
Ohio Legislature (Ohio Revised Code): section-5747.055, Ohio Legislature (Ohio Revised Code) (archived copy). Engine 1.7.0: IT 1040 line 4: each dependent gets the filer's stepped exemption amount; the Schedule of Credits retirement income credit (one per return, by the retirement income in Ohio AGI: $25 over $500 up to $200 over $8,000) and the $50 senior credit (per return, filer or spouse 65+), both while MAGI less exemptions is under $100,000, come before the joint filing credit; R.C. 5747.01(A)(4): disability benefits are deducted in full. Checked 2026-09-28.
Ohio Department of Taxation: scheduleofcredits.pdf, Ohio Department of Taxation. Engine 1.7.0: IT 1040 line 4: each dependent gets the filer's stepped exemption amount; the Schedule of Credits retirement income credit (one per return, by the retirement income in Ohio AGI: $25 over $500 up to $200 over $8,000) and the $50 senior credit (per return, filer or spouse 65+), both while MAGI less exemptions is under $100,000, come before the joint filing credit; R.C. 5747.01(A)(4): disability benefits are deducted in full. Checked 2026-10-12.
Ohio Legislature (Ohio Revised Code): section-5747.01, Ohio Legislature (Ohio Revised Code) (archived copy). Engine 1.7.0: IT 1040 line 4: each dependent gets the filer's stepped exemption amount; the Schedule of Credits retirement income credit (one per return, by the retirement income in Ohio AGI: $25 over $500 up to $200 over $8,000) and the $50 senior credit (per return, filer or spouse 65+), both while MAGI less exemptions is under $100,000, come before the joint filing credit; R.C. 5747.01(A)(4): disability benefits are deducted in full. Checked 2026-09-28.

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 Ohio IT 1040 / SD 100 Instructions, Ohio Department of Taxation. Taxable Social Security benefits from federal Form 1040 line 6b are deducted on the Ohio Schedule of Adjustments line 16, so Social Security is fully exempt. Checked 2026-10-12.

IRA, 401(k) and private pensions

No exclusion: pension, annuity and IRA/401(k) distributions are taxed as ordinary income.

2025 Ohio IT 1040 / SD 100 Instructions, Ohio Department of Taxation. Ohio starts from federal AGI with no pension or IRA exclusion; retirement income only earns a nonrefundable retirement income credit of at most $200 per return (MAGI less exemptions under $100,000). Engine 1.8.0: survivor benefits — a pension or annuity paid because of another person's death — are deducted (Schedule of Adjustments line 43); an inherited IRA, payable to the owner without a death, stays in. Checked 2026-10-12.
Publication 525, Internal Revenue Service. Line 42 does not reach disability pay converted to a retirement benefit at the plan's minimum retirement age (planMinimumRetirementAge, when given; else 65) (engine 1.8.0 final). Checked 2026-10-12.

Public pensions

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

2025 Ohio IT 1040 / SD 100 Instructions, Ohio Department of Taxation. Government pensions are included in federal AGI and taxed like other retirement income in Ohio (uniformed-services retirement income has its own deduction, which the engine applies to military pay). 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".

Military, Ohio Department of Taxation. Military retirement pay for service in the uniformed services, reserves or the Ohio National Guard is deductible. Checked 2026-10-12.

Wages

Wages are ordinary income.
Joint filing credit: a percentage of the tax when each spouse has at least $500 of qualifying income (wages or pensions; not interest or gains). Applied only on a joint return where each spouse's amounts and age are given.

It1040 booklet, Ohio Department of Taxation. Joint filing credit: each spouse needs at least $500 of qualifying income; the credit is a percentage of the tax, at most $650. Checked 2026-10-12.
Ohio Revised Code 5747.05 (Internet Archive copy), Ohio Legislative Service Commission. The joint filing credit is a percentage of the tax due after the credits that precede it, and for taxable years beginning in 2026 needs modified adjusted gross income under $500,000. Checked 2026-09-28.

Roth conversions

A conversion is taxed as ordinary income in full. It does not draw any retirement-income exclusion.

2025 Ohio IT 1040 / SD 100 Instructions, Ohio Department of Taxation. A traditional-to-Roth conversion is included in federal AGI, the Ohio starting point (IT 1040 line 1), and no Ohio deduction applies, so it is taxed as ordinary nonbusiness income. Checked 2026-10-12.

Capital gains

Net long-term gain is taxed as ordinary income.
Short-term gains are ordinary income.

2025 Ohio IT 1040 / SD 100 Instructions, Ohio Department of Taxation. Capital gains from personal investments are nonbusiness income taxed on the ordinary nonbusiness schedule; only gains that are business income get the business-income deduction and 3% rate. Checked 2026-10-12.
Ohio Revised Code §5747.01 (archived), Ohio Legislative Service Commission. The state return starts from federal adjusted gross income (federal taxable income in CO, IA, ND), so the federal capital-loss deduction (up to $3,000, $1,500 married filing separately) and its carryover are in the state base (engine 1.9.0: cap_loss_limit). Checked 2026-09-28.
2025 Schedule D (Form 1040), Capital Gains and Losses, Internal Revenue Service. The federal return deducts a net capital loss up to $3,000 ($1,500 married filing separately) on Form 1040 line 7a; a state that starts from federal adjusted gross income or federal taxable income carries that deduction. Checked 2026-10-12.

Blindness and disability

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

Ohio Department of Taxation: it1040-booklet.pdf, Ohio Department of Taxation. Engine 1.7.0: IT 1040 line 4: each dependent gets the filer's stepped exemption amount; the Schedule of Credits retirement income credit (one per return, by the retirement income in Ohio AGI: $25 over $500 up to $200 over $8,000) and the $50 senior credit (per return, filer or spouse 65+), both while MAGI less exemptions is under $100,000, come before the joint filing credit; R.C. 5747.01(A)(4): disability benefits are deducted in full. Engine 1.8.0: the disability deduction (line 42) does not cover a benefit that converted to a retirement benefit at the plan's minimum retirement age: planMinimumRetirementAge gives that age (engine 1.8.0 final); without it the engine ends the deduction at 65. Checked 2026-10-12.
Ohio Legislature (Ohio Revised Code): section-5747.025, Ohio Legislature (Ohio Revised Code) (archived copy). Engine 1.7.0: IT 1040 line 4: each dependent gets the filer's stepped exemption amount; the Schedule of Credits retirement income credit (one per return, by the retirement income in Ohio AGI: $25 over $500 up to $200 over $8,000) and the $50 senior credit (per return, filer or spouse 65+), both while MAGI less exemptions is under $100,000, come before the joint filing credit; R.C. 5747.01(A)(4): disability benefits are deducted in full. Checked 2026-09-28.
Ohio Legislature (Ohio Revised Code): section-5747.055, Ohio Legislature (Ohio Revised Code) (archived copy). Engine 1.7.0: IT 1040 line 4: each dependent gets the filer's stepped exemption amount; the Schedule of Credits retirement income credit (one per return, by the retirement income in Ohio AGI: $25 over $500 up to $200 over $8,000) and the $50 senior credit (per return, filer or spouse 65+), both while MAGI less exemptions is under $100,000, come before the joint filing credit; R.C. 5747.01(A)(4): disability benefits are deducted in full. Checked 2026-09-28.
Ohio Department of Taxation: scheduleofcredits.pdf, Ohio Department of Taxation. Engine 1.7.0: IT 1040 line 4: each dependent gets the filer's stepped exemption amount; the Schedule of Credits retirement income credit (one per return, by the retirement income in Ohio AGI: $25 over $500 up to $200 over $8,000) and the $50 senior credit (per return, filer or spouse 65+), both while MAGI less exemptions is under $100,000, come before the joint filing credit; R.C. 5747.01(A)(4): disability benefits are deducted in full. Checked 2026-10-12.
Ohio Legislature (Ohio Revised Code): section-5747.01, Ohio Legislature (Ohio Revised Code) (archived copy). Engine 1.7.0: IT 1040 line 4: each dependent gets the filer's stepped exemption amount; the Schedule of Credits retirement income credit (one per return, by the retirement income in Ohio AGI: $25 over $500 up to $200 over $8,000) and the $50 senior credit (per return, filer or spouse 65+), both while MAGI less exemptions is under $100,000, come before the joint filing credit; R.C. 5747.01(A)(4): disability benefits are deducted in full. Checked 2026-09-28.
IRS Publication 525, Internal Revenue Service. Engine 1.8.0: federally, a disability pension is taxed as a pension from the day after the minimum retirement age, the age at which a pension could first be received without the disability. Checked 2026-10-12.

Part-year and nonresident returns

Part-year resident (IT NRC): the tax a full-year resident would owe, less a credit for the share of income from outside the state.
Nonresident (IT NRC): the tax a full-year resident would owe, less a credit for the share of income from outside the state.
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 (cut, not rounded), at most 1.
The non-Ohio share is cut (not rounded) to four places.
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	Ohio's rule
One spouse a full-year resident, the other a part-year resident	a joint part-year / nonresident return is required.
One spouse a full-year resident, the other a nonresident	a joint part-year / nonresident return is required.
One spouse a part-year resident, the other a nonresident	a joint part-year / nonresident return is required.
Both part-year residents, different resident periods	a joint part-year / nonresident return is required.
Both nonresidents, only one with income from the state	a joint part-year / nonresident return is required.

2025 Ohio IT NRC - Ohio Nonresident Credit Calculation, Ohio Department of Taxation. Part-year / nonresident return (engine 1.12.0, residency): Checked 2026-10-12.
2025 Ohio IT 1040 / SD 100 Instructions (booklet), Ohio Department of Taxation. Part-year / nonresident return (engine 1.12.0, residency): Checked 2026-10-12.
2025 Ohio IT 1040 bundle incl. Ohio Schedule of Credits, Ohio Department of Taxation. Part-year / nonresident return (engine 1.12.0, residency): Checked 2026-10-12.
2025 Ohio IT 1040 / SD 100 Instructions (booklet), Ohio Department of Taxation. Married couples whose residency differs (engine 1.13.0): Checked 2026-10-06.
2025 Ohio IT NRC - Ohio Nonresident Credit Calculation, Ohio Department of Taxation. 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	$1,094
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	$2,536.13
Single, 60: $60,000 other ordinary income and a $50,000 Roth conversion	$2,588.38
Married filing jointly, 66: $30,000 IRA, a $40,000 Roth conversion, $30,000 Social Security ($25,500 federally taxable)	$1,172.38
Single, 58: $36,000 military retirement pay and $30,000 wages	$354.63
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	$897.38

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: $1,094

Line	Amount
Income total used by the income tests	$82,000
+ Other ordinary income in the base	$10,000
+ Retirement income in the base	$50,000
+ Long-term gain in the base	$5,000
− Personal exemption	$2,150
= State taxable income	$62,850
Tax from the rate schedule	$1,012
+ Fixed amount above the zero bracket	$332
= Tax before credits	$1,344
− Credits used (never more than the tax)	$250
− Retirement income credits	$200
− Senior credits (per return; senior head of household)	$50
= Tax	$1,094

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: $2,536.13

Line	Amount
Income total used by the income tests	$144,000
+ Other ordinary income in the base	$20,000
+ Retirement income in the base	$80,000
+ Long-term gain in the base	$10,000
− Personal exemption	$3,800
= State taxable income	$106,200
Tax from the rate schedule	$2,204.13
+ Fixed amount above the zero bracket	$332
= Tax before credits	$2,536.13
= Tax	$2,536.13

Single, 60: $60,000 other ordinary income and a $50,000 Roth conversion: $2,588.38

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
− Personal exemption	$1,900
= State taxable income	$108,100
Tax from the rate schedule	$2,256.38
+ Fixed amount above the zero bracket	$332
= Tax before credits	$2,588.38
= Tax	$2,588.38

Married filing jointly, 66: $30,000 IRA, a $40,000 Roth conversion, $30,000 Social Security ($25,500 federally taxable): $1,172.38

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
− Personal exemption	$4,300
= State taxable income	$65,700
Tax from the rate schedule	$1,090.38
+ Fixed amount above the zero bracket	$332
= Tax before credits	$1,422.38
− Credits used (never more than the tax)	$250
− Retirement income credits	$200
− Senior credits (per return; senior head of household)	$50
= Tax	$1,172.38

Single, 58: $36,000 military retirement pay and $30,000 wages: $354.63

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
− Personal exemption	$2,400
= State taxable income	$27,600
Tax from the rate schedule	$42.63
+ Fixed amount above the zero bracket	$332
= Tax before credits	$374.63
Per-exemption credit	$20
− Credits used (never more than the tax)	$20
= Tax	$354.63

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: $897.38

Line	Amount
Income total used by the income tests	$85,500
+ Other ordinary income in the base	$10,000
+ Retirement income in the base	$50,000
− Personal exemption	$4,300
= State taxable income	$55,700
Tax from the rate schedule	$815.38
+ Fixed amount above the zero bracket	$332
= Tax before credits	$1,147.38
− Credits used (never more than the tax)	$250
− Retirement income credits	$200
− Senior credits (per return; senior head of household)	$50
= Tax	$897.38

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 Ohio'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), `bracket_cliff_threshold`	Indexed: GDP implicit price deflator (BEA), percentage increase over the preceding calendar year, applied each August to the prior year's adjusted amount; the increase rounded to the nearest $50.	R.C. 5747.02(A)(5): each August the commissioner adjusts the income amounts of (A)(2)-(3) (the $26,050 zero-bracket threshold) by the percentage increase in the GDP deflator, rounding to the nearest $50, never downward. The 2.75% rate applies above the threshold for 2026 and thereafter. Ohio Rev. Code 5747.02 (Wayback copy of codes.ohio.gov) (Ohio Legislative Service Commission, statute): Indexing clause, nearest $50. Quoted: "in August of each year, the tax commissioner shall make a new adjustment to the income amounts prescribed in divisions (A)(2) and (3) of this section"; "rounding the resulting sum to the nearest multiple of fifty dollars"; "For taxable years beginning in 2026 and thereafter, $332.00 plus 2.75% of the amount in excess of $26,050.". Checked 2026-09-30.
`bracket_cliff_amount`	Defined from another amount: 1.27448% of `bracket_cliff_threshold` as projected, the value rounded to the nearest $0.01.	R.C. 5747.02(A)(5): when the commissioner adjusts the $26,050 threshold, the tax owed at it is recomputed as the (A)(2) rate (1.27448%) times the adjusted threshold ($332.00 for 2026 = 1.27448% x $26,050, to the cent as the statute prints it). The projection recomputes it from the projected threshold, so it moves in $50 steps with it rather than with the factor. Ohio Rev. Code 5747.02 (Wayback copy of codes.ohio.gov) (Ohio Legislative Service Commission, statute): Recomputation of the tax dollar amount. Quoted: "To recompute the tax dollar amount corresponding to the lowest tax rate in division (A)(3) of this section, the commissioner shall multiply the tax rate prescribed in division (A)(2) of this section by the income amount specified in that division". Checked 2026-09-30.
`exemption_tier_amount`	Indexed: GDP implicit price deflator (BEA), percentage increase over the preceding calendar year, applied each August to the prior year's adjusted amount; the increase rounded up to a multiple of $50.	R.C. 5747.025(B)-(C): the personal exemption amounts are adjusted each August by the percentage increase in the GDP deflator for the preceding calendar year, rounded UP to the nearest $50, never downward ($2,400/$2,150/$1,900 for 2026). Ohio Rev. Code 5747.025 (Wayback copy of codes.ohio.gov) (Ohio Legislative Service Commission, statute): Indexing clause, upward $50 rounding. Quoted: "shall determine the percentage increase in the gross domestic product deflator determined by the bureau of economic analysis"; "rounding the resulting sum upward to the nearest multiple of fifty dollars". Checked 2026-10-12.
`exemption_tier_agi_single`, `exemption_tier_agi_joint`	Fixed in law: held at the rules-year amount in every later year.	R.C. 5747.025(A): the exemption tiers turn on modified AGI of $40,000 and $80,000, and no exemption is allowed at $500,000 or more for 2026 and thereafter; only the exemption amounts are indexed. Ohio Rev. Code 5747.025 (Wayback copy of codes.ohio.gov) (Ohio Legislative Service Commission, statute): Fixed tier limits. Quoted: "is less than or equal to forty thousand dollars"; "five hundred thousand dollars for taxable years beginning in 2026 or thereafter". Checked 2026-10-12.
`joint_filing_credit_agi_limit`, `oh-joint-filing-credit-bands` (a table held in code)	Fixed in law: held at the rules-year amount in every later year.	R.C. 5747.05(E): each spouse needs $500 of qualifying income; the credit is 20%/15%/10%/5% at income less exemptions of $25,000/$50,000/$75,000/above, at most $650, and not allowed at modified AGI of $500,000 or more from 2026; no adjustment provision. Ohio Rev. Code 5747.05 (Wayback copy of codes.ohio.gov) (Ohio Legislative Service Commission, statute): Fixed joint filing credit amounts. Quoted: "each of whom had adjusted gross income of at least five hundred dollars"; "a credit equal to the lesser of six hundred fifty dollars"; "or less than five hundred thousand dollars for taxable years beginning in 2026 or thereafter". Checked 2026-09-30.
`low_income_exemption_credit`, `low_income_exemption_credit_limit`	Fixed in law: held at the rules-year amount in every later year.	R.C. 5747.022: $20 per exemption when modified AGI less exemptions is under $30,000; fixed amounts. Ohio Rev. Code 5747.022 (Wayback copy of codes.ohio.gov) (Ohio Legislative Service Commission, statute): Fixed $20 / $30,000. Quoted: "is less than thirty thousand dollars may claim a credit equal to twenty dollars times the number of exemptions". Checked 2026-09-30.
`ret_credit_limit`, `ret_credit_amount`, `ret_credit_top`, `ret_credit_income_limit`, `retiree_senior_credit`	Fixed in law: held at the rules-year amount in every later year.	R.C. 5747.055(B) and (F): the retirement income credit schedule ($0-$200 by retirement income up to $500/$1,500/$3,000/$5,000/$8,000/over) and the $50 senior credit, both only while modified AGI less exemptions is under $100,000; fixed amounts. Ohio Rev. Code 5747.055 (Wayback copy of codes.ohio.gov) (Ohio Legislative Service Commission, statute): Fixed schedule and $50 credit. Quoted: "is less than one hundred thousand dollars. Only one such credit shall be allowed for each return"; "Over $5,000 but not more than $8,000"; "A credit equal to fifty dollars for each return required to be filed". Checked 2026-10-12.
`retiree_senior_credit_min_age`	Attained age: the same age in every year.	The $50 senior credit is for taxpayers 65 years of age or older during the taxable year: a fixed attained age. Ohio Rev. Code 5747.055 (Wayback copy of codes.ohio.gov) (Ohio Legislative Service Commission, statute): Age 65. Quoted: "for taxpayers sixty-five years of age or older during the taxable year". Checked 2026-10-12.
`dis_income_max_age`, `dis_plan_age_rule`	Attained age: the same age in every year.	Ohio's line 42 deducts disability benefits, but not retirement benefits that converted from disability benefits at the plan's minimum retirement age (engine default 65); attained-age tests, not dollar amounts. 2025 Ohio IT 1040 Instructions (Ohio Department of Taxation, instructions): Converted disability benefits are not deductible. Quoted: "Retirement benefits that converted from disability benefits upon reaching a minimum retirement age". Checked 2026-10-12.
`eic_max_credit`	Tied to an indexed federal amount: federal earned income credit maximum, IRC 32(b)/(j) (chained CPI-U); not rounded (the statute states no rounding).	The maximum federal EIC (credit percentage x the earned income amount) moves with the earned income amount, indexed under IRC 32(j)(1) by the chained CPI and rounded to the nearest $10 (32(j)(2)(A)); the credit itself is the rate times that rounded amount (2026: $664/$4,427/$7,316/$8,231). 26 U.S.C. 32 (earned income credit) (Cornell LII (U.S. Code), federal): 32(j) indexing and $10 rounding of the (b)(2)(A) amounts. Quoted: "each of the dollar amounts in subsections (b)(2) and (i)(1) shall be increased by an amount equal to"; "such dollar amount shall be rounded to the nearest multiple of $10.". Checked 2026-10-12. Rev. Proc. 2025-32 (2026 inflation adjustments) (Internal Revenue Service, federal): 2026 federal EIC table. Quoted: "For taxable years beginning in 2026, the following amounts are used to determine the earned income credit under § 32(b).". Checked 2026-10-12.
`eic_phaseout_start`, `eic_phaseout_start_mfj`	Tied to an indexed federal amount: federal EIC threshold phase-out amounts, IRC 32(b)(2)/(j) (chained CPI-U); the increase rounded to the nearest $10.	The federal EIC threshold phase-out amounts (and the joint-return increase) are indexed under IRC 32(j)(1) by the chained CPI and rounded to the nearest $10 (2026: $10,860/$23,890; joint $18,140/$31,160). 26 U.S.C. 32 (earned income credit) (Cornell LII (U.S. Code), federal): Indexing and $10 rounding. Quoted: "each of the dollar amounts in subsections (b)(2) and (i)(1) shall be increased by an amount equal to"; "such dollar amount shall be rounded to the nearest multiple of $10.". Checked 2026-10-12. Rev. Proc. 2025-32 (2026 inflation adjustments) (Internal Revenue Service, federal): 2026 table. Quoted: "For taxable years beginning in 2026, the following amounts are used to determine the earned income credit under § 32(b).". Checked 2026-10-12.
`eic_invest_limit`	Tied to an indexed federal amount: federal EIC disqualified income limit, IRC 32(i)(1)/(j) (chained CPI-U); the increase rounded down to a multiple of $50.	The federal EIC disqualified-investment-income limit (IRC 32(i)(1)) is indexed under 32(j)(1) and rounded down to $50 (32(j)(2)(B)); $12,200 for 2026. 26 U.S.C. 32 (earned income credit) (Cornell LII (U.S. Code), federal): Indexing and $50 rounding. Quoted: "is not a multiple of $50, such amount shall be rounded to the next lowest multiple of $50.". Checked 2026-10-12. Rev. Proc. 2025-32 (2026 inflation adjustments) (Internal Revenue Service, federal): 2026 limit. Quoted: "if the aggregate amount of certain investment income exceeds $12,200". Checked 2026-10-12.
`eic_nochild_max_age`, `eic_nochild_min_age`	Attained age: the same age in every year.	Without a qualifying child the federal EIC requires the filer (or spouse) to have attained age 25 but not age 65 before the end of the year: fixed attained ages. 26 U.S.C. 32 (earned income credit) (Cornell LII (U.S. Code), federal): Ages 25 and 65. Quoted: "has attained age 25 but not attained age 65 before the close of the taxable year". Checked 2026-10-12.
`cap_loss_limit`, `cap_loss_limit_mfs`	Fixed in law: held at the rules-year amount in every later year.	The state follows the federal net capital loss limit of IRC 1211(b): $3,000 ($1,500 MFS), a fixed amount with no inflation adjustment. 26 U.S.C. 1211 (limitation on capital losses) (Cornell LII (U.S. Code), federal): The capital-loss deduction against ordinary income is a fixed $3,000 ($1,500 MFS); section 1211 contains no inflation adjustment. Quoted: "$3,000 ($1,500 in the case of a married individual filing a separate return), or". 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

MAGI is taken as Ohio AGI; the business income deduction Ohio adds back is not an engine input.
The per-exemption amounts are 2025's; Ohio indexes them each August and the 2026 figures were not yet published.
The engine does not round lines to whole dollars as the form does (differences under $1).
Disability pay (disabilityIncome) is deducted on line 42 before the plan's minimum retirement age given in planMinimumRetirementAge (engine 1.8.0); without it the engine reads 65, so disability pay from a plan whose minimum retirement age is under 65 and not given is over-deducted between that age and 65.
The Ohio earned income credit is 30% of the federal credit computed by the engine from the wages and qualifying children, nonrefundable (engine 1.8.0, DIFF-OH-F1).
The child and dependent care credit needs expenses and is not calculated. Sources: 2025 Ohio IT 1040 / SD 100 Instructions (checked 2026-10-12); Section 5747.02 (checked 2026-09-28); Section 5747.025 (checked 2026-09-28); 2025 Ohio IT 1040 / SD 100 Instructions (checked 2026-10-12); Ohio Legislature (Ohio Revised Code): section-5747.055 (checked 2026-09-28); Ohio Department of Taxation: scheduleofcredits.pdf (checked 2026-10-12); Ohio Legislature (Ohio Revised Code): section-5747.01 (checked 2026-09-28).
The lump-sum retirement and lump-sum distribution credits are not calculated: they need the lump-sum facts. Sources: 2025 Ohio IT 1040 / SD 100 Instructions (checked 2026-10-12); Publication 525 (checked 2026-10-12).
The unreimbursed medical and health care expense deduction (Ohio Schedule of Adjustments line 44) is not calculated. Sources: 2025 Ohio IT 1040 / SD 100 Instructions (checked 2026-10-12); Section 5747.02 (checked 2026-09-28); Section 5747.025 (checked 2026-09-28); 2025 Ohio IT 1040 / SD 100 Instructions (checked 2026-10-12); Ohio Legislature (Ohio Revised Code): section-5747.055 (checked 2026-09-28); Ohio Department of Taxation: scheduleofcredits.pdf (checked 2026-10-12); Ohio Legislature (Ohio Revised Code): section-5747.01 (checked 2026-09-28).

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 backend/tests/test_state_worksheets_3.c replays the IT 1040 (2025 booklet with the 2026 R.C. 5747.02 schedule and $500,000 cutoffs) line by line, including the joint filing credit, through the API.

Golden scenarios (hand-computed expected tax, asserted to within $1): OH2.
State-specific unit tests: test_oh_mfs_single_schedule, test_localities_endpoint, test_prop_l3_1140, test_absent_is_unchanged, test_incoherent_inputs_clamped, test_prop_l3, test_oh_joint_filing_credit, test_c_states, test_worked_ratios, test_engine_paths, test_oh_base_amount_and_exemption_tiers, test_oh_jfc_after_exemption_credit.
Structural tests covering every state: 8.
State forms and worksheets followed in the test derivations: IT 1040 lines 1-5, 7, 8a (2026 schedule: $332 plus 2.75% over $26,050); IT 1040 line 4 exemption table ($2,400 / $2,150 / $1,900 by MAGI); Ohio Schedule of Adjustments lines 16 (taxable Social Security) and 34 (uniformed services retirement income); Ohio Schedule of Credits line 12 (joint filing credit, 5% / 10% / 15% bands); Ohio Schedule of Credits line 9 (exemption credit) and line 12 on the tax after the preceding credits.