State tax docs / States / Utah

Utah state income tax: engine rules, 2026

How the QuantCalc engine computes Utah 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 · 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 UT).

How the tax is computed

Every step the engine takes for Utah, 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 Utah'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	joint schedule, thresholds halved	single schedule
Top rate	4.45% flat	4.45% flat	4.45% flat	4.45% flat
Standard deduction (a credit base instead)	none	none	none	none
Standard deduction at 70	none	none	none	none
Personal exemption	none	none	none	none
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.
Utah's values · engine step (select_brackets). Sources (Rate schedule): Utah Code 59-10-104. Tax basis -- Tax rate -- Exemption (effective 1/1/2026) (checked 2026-09-28); NEWS RELEASE: Gov. Cox signs 87 bills in the 2026 General Legislative Session (checked 2026-10-12); Tax Rates (2025 Utah Income Tax) (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).
Utah's values · engine step (select_brackets). Sources (Rate schedule): Utah Code 59-10-104. Tax basis -- Tax rate -- Exemption (effective 1/1/2026) (checked 2026-09-28); NEWS RELEASE: Gov. Cox signs 87 bills in the 2026 General Legislative Session (checked 2026-10-12); Tax Rates (2025 Utah Income Tax) (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.
Utah's values · engine step (select_brackets). Sources (Rate schedule): Utah Code 59-10-104. Tax basis -- Tax rate -- Exemption (effective 1/1/2026) (checked 2026-09-28); NEWS RELEASE: Gov. Cox signs 87 bills in the 2026 General Legislative Session (checked 2026-10-12); Tax Rates (2025 Utah Income Tax) (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.
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.
Utah's values · engine step (compute_state_tax_detail). Sources (Military retirement pay): Tc 40a (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).
Utah's values · engine step (compute_state_tax_detail). Sources (Capital gains): TC-40 – Line-by-Line Instructions (2025 Utah Income Tax) (checked 2026-10-12); TC-40A – Supplemental Schedule Instructions (2025 Utah Income Tax) (checked 2026-10-12); TC-40 line-by-line instructions (checked 2026-10-12); 2025 Schedule D (Form 1040), Capital Gains and Losses (checked 2026-10-12)
Which Social Security threshold applies Joint returns use the joint threshold; head of household uses it too where the state says so, otherwise the single one; married filing separately uses its own threshold where set, else the single one. Benefits are tested against the income total above.
Utah's values · engine step (ss_amount_in_state_base). Sources (Social Security): Utah Code 59-10-1042. Nonrefundable tax credit for social security benefits (effective 1/1/2026) (checked 2026-10-12); TC-40A – Supplemental Schedule Instructions (2025 Utah Income Tax) (checked 2026-10-12); TC-40 Line-by-Line Instructions (checked 2026-10-12)
Social Security: credit phase-out The credit removes the tax on benefits at or below the threshold. Above it the credit falls by 2.5% per dollar over; the engine carries this as the taxed share of benefits rising by that rate divided by the tax rate per dollar over, up to all of it.
Utah's values · engine step (ss_amount_in_state_base). Sources (Social Security): Utah Code 59-10-1042. Nonrefundable tax credit for social security benefits (effective 1/1/2026) (checked 2026-10-12); TC-40A – Supplemental Schedule Instructions (2025 Utah Income Tax) (checked 2026-10-12); TC-40 Line-by-Line 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.
Utah's values · engine step (compute_state_tax_detail). Sources (IRA, 401(k) and private pensions): TC-40 – Line-by-Line Instructions (2025 Utah Income Tax) (checked 2026-10-12); TC-40A – Supplemental Schedule Instructions (2025 Utah Income Tax) (checked 2026-10-12); TC-40A Instructions (Utah Individual Income Tax) (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.
Utah's values · engine step (compute_state_tax_detail). Sources (Roth conversions): TC-40 – Line-by-Line Instructions (2025 Utah Income Tax) (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.
Utah's values · engine step (compute_state_tax_detail). Sources (Capital gains): TC-40 – Line-by-Line Instructions (2025 Utah Income Tax) (checked 2026-10-12); TC-40A – Supplemental Schedule Instructions (2025 Utah Income Tax) (checked 2026-10-12); TC-40 line-by-line instructions (checked 2026-10-12); 2025 Schedule D (Form 1040), Capital Gains and Losses (checked 2026-10-12)
Taxpayer credit instead of a deduction No deduction is subtracted: the deduction amount (plus the federal additional amount per taxpayer 65 or older) becomes the base of the credit applied after the schedule. The federal blind amount joins the base the same way, per blind person.
Utah's values · engine step (compute_state_tax_detail). Sources (Deductions, exemptions and credits): Utah Code 59-10-1018. Definitions -- Nonrefundable taxpayer tax credits (effective 1/1/2026) (checked 2026-10-05); TC-40 – Line-by-Line Instructions (2025 Utah Income Tax) (checked 2026-10-12); IRS releases tax inflation adjustments for tax year 2026, including amendments from the One, Big, Beautiful Bill (checked 2026-10-12); Rp 25 32 (checked 2026-10-12); IRS releases tax inflation adjustments for tax year 2026 (checked 2026-10-12); Utah State Legislature: C59-10-S1047_2026050620260506.html (checked 2026-09-28); Utah Individual Income Tax: TC-40A credits (Earned Income Tax Credit, code AM, UCA 59-10-1044), tax year 2025 (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.
Utah's values · engine step (compute_state_tax_detail). Sources (Rate schedule): Utah Code 59-10-104. Tax basis -- Tax rate -- Exemption (effective 1/1/2026) (checked 2026-09-28); NEWS RELEASE: Gov. Cox signs 87 bills in the 2026 General Legislative Session (checked 2026-10-12); Tax Rates (2025 Utah Income Tax) (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.
Utah's values · engine step (apply_state_brackets). Sources (Rate schedule): Utah Code 59-10-104. Tax basis -- Tax rate -- Exemption (effective 1/1/2026) (checked 2026-09-28); NEWS RELEASE: Gov. Cox signs 87 bills in the 2026 General Legislative Session (checked 2026-10-12); Tax Rates (2025 Utah Income Tax) (checked 2026-10-12)
Child credits only when the caller lists dependents A credit per dependent at or under the child age and another per older dependent; none above an income limit where there is one; where the credit is a share of the federal child tax credit, the share of the federal credit the household is allowed (the nonrefundable part up to the federal tax, the refundable part from earned income); reduced per dollar over a threshold, or by a percentage per thousand dollars over a start, where the state says so. Also a credit per disabled dependent child at or under an age, while income is at most the limit. Where the state says so, the child credit is prorated by the state AGI (the base before deductions) over the federal AGI when the state AGI is lower. The federal tax that limits the nonrefundable part is the tax before credits when given; with only the tax after the nonrefundable credits, any tax left means the whole credit was allowed, and none left means the nonrefundable part is taken as zero. Where the state says so, the refundable part for three or more children is the larger of the earned-income route and the Social-Security-tax route.
Utah's values · engine step (compute_state_tax_detail). Sources (Deductions, exemptions and credits): Utah Code 59-10-1018. Definitions -- Nonrefundable taxpayer tax credits (effective 1/1/2026) (checked 2026-10-05); TC-40 – Line-by-Line Instructions (2025 Utah Income Tax) (checked 2026-10-12); IRS releases tax inflation adjustments for tax year 2026, including amendments from the One, Big, Beautiful Bill (checked 2026-10-12); Rp 25 32 (checked 2026-10-12); IRS releases tax inflation adjustments for tax year 2026 (checked 2026-10-12); Utah State Legislature: C59-10-S1047_2026050620260506.html (checked 2026-09-28); Utah Individual Income Tax: TC-40A credits (Earned Income Tax Credit, code AM, UCA 59-10-1044), tax year 2025 (checked 2026-10-12)
Taxpayer tax credit The credit rate times the credit base, less the phase-out rate times taxable income above the filing status's base, not below zero.
Utah's values · engine step (compute_state_tax_detail). Sources (Deductions, exemptions and credits): Utah Code 59-10-1018. Definitions -- Nonrefundable taxpayer tax credits (effective 1/1/2026) (checked 2026-10-05); TC-40 – Line-by-Line Instructions (2025 Utah Income Tax) (checked 2026-10-12); IRS releases tax inflation adjustments for tax year 2026, including amendments from the One, Big, Beautiful Bill (checked 2026-10-12); Rp 25 32 (checked 2026-10-12); IRS releases tax inflation adjustments for tax year 2026 (checked 2026-10-12); Utah State Legislature: C59-10-S1047_2026050620260506.html (checked 2026-09-28); Utah Individual Income Tax: TC-40A credits (Earned Income Tax Credit, code AM, UCA 59-10-1044), tax year 2025 (checked 2026-10-12)
Taxpayer credit phase-out counts all taxable Social Security The phase-out income adds back the Social Security the Social Security credit offsets, since the state's taxable income includes it.
Utah's values · engine step (compute_state_tax_detail). Sources (Social Security): Utah Code 59-10-1042. Nonrefundable tax credit for social security benefits (effective 1/1/2026) (checked 2026-10-12); TC-40A – Supplemental Schedule Instructions (2025 Utah Income Tax) (checked 2026-10-12); TC-40 Line-by-Line Instructions (checked 2026-10-12)
Retirement credit instead of the Social Security and military credits Per person at or above the age (a birth-year cutoff), less the phase-out rate times the income total above the filing status's start. It cannot be combined with the Social Security or military credit, so the engine takes whichever is larger; choosing it puts back the tax the Social Security credit removed.
Utah's values · engine step (compute_state_tax_detail). Sources (IRA, 401(k) and private pensions): TC-40 – Line-by-Line Instructions (2025 Utah Income Tax) (checked 2026-10-12); TC-40A – Supplemental Schedule Instructions (2025 Utah Income Tax) (checked 2026-10-12); TC-40A Instructions (Utah Individual Income Tax) (checked 2026-10-12)
Military retirement credit The credit rate times the military pay.
Utah's values · engine step (compute_state_tax_detail). Sources (Military retirement pay): Tc 40a (checked 2026-10-12)
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).
Utah's values · engine step (state_tax_effective_config). Sources (Rate schedule): Utah Code 59-10-104. Tax basis -- Tax rate -- Exemption (effective 1/1/2026) (checked 2026-09-28); NEWS RELEASE: Gov. Cox signs 87 bills in the 2026 General Legislative Session (checked 2026-10-12); Tax Rates (2025 Utah Income Tax) (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.
Utah's values · engine step (compute_state_tax_detail). Sources (Social Security): Utah Code 59-10-1042. Nonrefundable tax credit for social security benefits (effective 1/1/2026) (checked 2026-10-12); TC-40A – Supplemental Schedule Instructions (2025 Utah Income Tax) (checked 2026-10-12); TC-40 Line-by-Line 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.
Utah's values · engine step (compute_state_tax_detail). Sources (Capital gains): TC-40 – Line-by-Line Instructions (2025 Utah Income Tax) (checked 2026-10-12); TC-40A – Supplemental Schedule Instructions (2025 Utah Income Tax) (checked 2026-10-12); TC-40 line-by-line instructions (checked 2026-10-12); 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).
Utah's values · engine step (compute_state_tax_detail). Sources (Social Security): Utah Code 59-10-1042. Nonrefundable tax credit for social security benefits (effective 1/1/2026) (checked 2026-10-12); TC-40A – Supplemental Schedule Instructions (2025 Utah Income Tax) (checked 2026-10-12); TC-40 Line-by-Line Instructions (checked 2026-10-12)
Nonrefundable earned income credits SC, UT, DE and VA: a share of the federal EIC, nonrefundable, with the other credits (SC at most $200; DE, or its refundable share, the larger; VA, the larger of it and the credit for low-income individuals ($300 per exemption at a family income within the poverty guideline), or the refundable share, the larger).
Utah's values · engine step (st_compute). Sources (Deductions, exemptions and credits): Utah Code 59-10-1018. Definitions -- Nonrefundable taxpayer tax credits (effective 1/1/2026) (checked 2026-10-05); TC-40 – Line-by-Line Instructions (2025 Utah Income Tax) (checked 2026-10-12); IRS releases tax inflation adjustments for tax year 2026, including amendments from the One, Big, Beautiful Bill (checked 2026-10-12); Rp 25 32 (checked 2026-10-12); IRS releases tax inflation adjustments for tax year 2026 (checked 2026-10-12); Utah State Legislature: C59-10-S1047_2026050620260506.html (checked 2026-09-28); Utah Individual Income Tax: TC-40A credits (Earned Income Tax Credit, code AM, UCA 59-10-1044), tax year 2025 (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).
Utah's values · engine step (state_tax_refundable_credits). Sources (Deductions, exemptions and credits): Utah Code 59-10-1018. Definitions -- Nonrefundable taxpayer tax credits (effective 1/1/2026) (checked 2026-10-05); TC-40 – Line-by-Line Instructions (2025 Utah Income Tax) (checked 2026-10-12); IRS releases tax inflation adjustments for tax year 2026, including amendments from the One, Big, Beautiful Bill (checked 2026-10-12); Rp 25 32 (checked 2026-10-12); IRS releases tax inflation adjustments for tax year 2026 (checked 2026-10-12); Utah State Legislature: C59-10-S1047_2026050620260506.html (checked 2026-09-28); Utah Individual Income Tax: TC-40A credits (Earned Income Tax Credit, code AM, UCA 59-10-1044), tax year 2025 (checked 2026-10-12)

Rate schedule

A flat 4.45% on state taxable income.

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

The Tax Commission's own pages (tax-rates page, TC-40 line 10) still show the TY2025 rate of 4.5%; the 4.45% rate for 2026 is established only by the statute text (59-10-104 as amended by 2026 S.B. 60).

Utah Code 59-10-104. Tax basis -- Tax rate -- Exemption (effective 1/1/2026), Utah State Legislature (Utah Code; Internet Archive capture). Utah Code 59-10-104 (effective 1/1/2026, amended by 2026 S.B. 60, ch. 250) taxes a resident's entire state taxable income at a single 4.45% rate, the same for every filing status. Checked 2026-09-28.
NEWS RELEASE: Gov. Cox signs 87 bills in the 2026 General Legislative Session, Office of the Governor of Utah. The Governor signed S.B. 60 (Income Tax Rate Amendments), the 2026 income-tax rate cut, on March 23, 2026. Checked 2026-10-12.
Tax Rates (2025 Utah Income Tax), Utah State Tax Commission. The Tax Commission's rate history shows Utah's single flat rate for all income levels (4.5% from January 1, 2025, before the 2026 cut to 4.45%). Checked 2026-10-12.

Deductions, exemptions and credits

No deduction is subtracted: the full income is taxed, and a nonrefundable taxpayer credit of 6% of $16,100 (single) / $32,200 (MFJ) is applied instead, reduced by 1.3% of taxable income above $18,213 (single), $36,426 (MFJ) or $27,320 (head of household). The credit base includes the federal additional standard deduction for each taxpayer 65 or older ($2,050 unmarried, $1,650 per married taxpayer).

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

TY2026 indexed phase-out bases (59-10-1018(5)) not published on any fetchable page; engine uses the TY2025 $18,213/$36,426/$27,320.

Utah Code 59-10-1018. Definitions -- Nonrefundable taxpayer tax credits (effective 1/1/2026), Utah State Legislature (Utah Code; Internet Archive capture). Utah has no standard deduction; instead a nonrefundable taxpayer tax credit equals 6% of the federal standard (or Utah itemized) deduction plus 6% of the Utah personal exemption, reduced by $0.013 per dollar of state taxable income over a CPI-indexed base. Engine 1.7.0: TC-40 line 11: the $2,111 Utah personal exemption per qualifying dependent (TY2025; one more in a dependent's birth year) joins the taxpayer credit base; 59-10-1047: a nonrefundable $1,000 per child under 6, less 10 cents per dollar of income over $49,000 single / HOH, $61,000 joint, $30,500 MFS (the 2026 statute text). Checked 2026-10-05.
TC-40 – Line-by-Line Instructions (2025 Utah Income Tax), Utah State Tax Commission. The TC-40 instructions compute the taxpayer tax credit as 6% of the federal standard/itemized deduction plus exemptions, less 1.3% of Utah taxable income over $18,213 single/MFS, $36,426 MFJ or $27,320 HOH (TY2025 indexed bases). Engine 1.7.0: TC-40 line 11: the $2,111 Utah personal exemption per qualifying dependent (TY2025; one more in a dependent's birth year) joins the taxpayer credit base; 59-10-1047: a nonrefundable $1,000 per child under 6, less 10 cents per dollar of income over $49,000 single / HOH, $61,000 joint, $30,500 MFS (the 2026 statute text). Checked 2026-10-12.
IRS releases tax inflation adjustments for tax year 2026, including amendments from the One, Big, Beautiful Bill, Internal Revenue Service. The 2026 federal standard deduction is $16,100 single / $32,200 MFJ; Utah's taxpayer credit is 6% of this amount, which the engine carries in std_deduction_* as the credit base. Checked 2026-10-12.
Rp 25 32, irs.gov. irs.gov: "the additional standard deduction amount under § 63(f) for the aged or the blind is $1,650. The additional standard deduction amount is increased to $2,050 if the individual is also unmarried and not a surviving spouse." Checked 2026-10-12.
IRS releases tax inflation adjustments for tax year 2026, Internal Revenue Service. The 2026 federal standard deduction for heads of household, which the TC-40 taxpayer tax credit uses as the head-of-household base. Checked 2026-10-12.
Utah State Legislature: C59-10-S1047_2026050620260506.html, Utah State Legislature (archived copy). Engine 1.7.0: TC-40 line 11: the $2,111 Utah personal exemption per qualifying dependent (TY2025; one more in a dependent's birth year) joins the taxpayer credit base; 59-10-1047: a nonrefundable $1,000 per child under 6, less 10 cents per dollar of income over $49,000 single / HOH, $61,000 joint, $30,500 MFS (the 2026 statute text). Checked 2026-09-28.
Utah Individual Income Tax: TC-40A credits (Earned Income Tax Credit, code AM, UCA 59-10-1044), tax year 2025, Utah State Tax Commission. Earned income credit (engine 1.12.0): 20% of the federal EIC, nonrefundable. Checked 2026-10-12.

Social Security

Benefits are in the base, but a credit removes the tax on them when income is at or below $54,000 (single), $45,000 (married filing separately) and $90,000 (married filing jointly and head of household). Above it the credit falls by 2.5% of each dollar of income over the threshold; the engine models this as the taxed share of benefits rising by 2.5% / 4.45% per dollar over.

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

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

The statute's modified AGI adds tax-exempt interest and 59-10-114 additions to AGI; the engine tests plain AGI. The TC-40A worksheet line uses Utah taxable income (line 9) plus tax-exempt interest rather than AGI.

Utah Code 59-10-1042. Nonrefundable tax credit for social security benefits (effective 1/1/2026), Utah State Legislature (Utah Code; Internet Archive capture). Social Security included in Utah income is taxed at the flat rate but offset by a nonrefundable credit equal to the 59-10-104 rate times the included benefits, reduced by $0.025 per dollar of modified AGI over $54,000 single, $90,000 joint or head of household, and $45,000 married filing separately. Checked 2026-10-12.
TC-40A – Supplemental Schedule Instructions (2025 Utah Income Tax), Utah State Tax Commission. The TY2025 Social Security Credit Worksheet (code AH) multiplies taxable benefits by the flat rate and reduces the credit by 0.025 times income over $54,000 single, $90,000 joint/HOH/surviving spouse, $45,000 MFS; it cannot be combined with the $450 retirement credit. Checked 2026-10-12.
TC-40 Line-by-Line Instructions, Utah State Tax Commission. The taxpayer tax credit phase-out (line 18) runs on line 9, Utah taxable income, which includes all federally taxable Social Security; the Social Security credit is a separate TC-40A credit. Checked 2026-10-12.

IRA, 401(k) and private pensions

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

TC-40 – Line-by-Line Instructions (2025 Utah Income Tax), Utah State Tax Commission. Utah's computation starts from federal adjusted gross income (TC-40 line 4), so IRA, 401(k) and private pension distributions included in federal AGI are taxed at the flat rate; there is no general retirement-income subtraction. Checked 2026-10-12.
TC-40A – Supplemental Schedule Instructions (2025 Utah Income Tax), Utah State Tax Commission. The only general retirement relief is a $450 retirement credit limited to filers born on or before Dec. 31, 1952, which cannot be combined with the Social Security credit; the only retirement subtraction is for income previously taxed by another state. Checked 2026-10-12.
TC-40A Instructions (Utah Individual Income Tax), Utah State Tax Commission. The Retirement Credit is $450 per person born on or before December 31, 1952, less 2.5% of MAGI over $25,000 single, $32,000 joint or head of household, $16,000 married filing separately; it cannot be claimed together with the Social Security or military retirement credit. 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):

No page states in so many words that civil-service/state pensions are fully taxable; this follows from FAGI being the starting point with no public-pension subtraction listed among the TC-40A subtractions.

TC-40A – Supplemental Schedule Instructions (2025 Utah Income Tax), Utah State Tax Commission. Utah has no subtraction for government pensions: they are taxed like other pension income through federal AGI, with only railroad retirement subtracted and military retirement eligible for a separate credit. Checked 2026-10-12.

Military retirement pay

Military retirement pay is taxed, then a nonrefundable credit of 4.45% of the military pay in the base is applied, per person.
Military pay the military rule does not exempt is pension income under the general retirement rules.
Rules are applied per taxpayer at that person's own age when the spouse's age is given. API value: rules.militaryRetirement.treatment: "credit".

Tc 40a, Utah State Tax Commission. A nonrefundable military retirement credit applies per person, at the flat rate times the military retirement pay taxed. Checked 2026-10-12.

Roth conversions

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

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

No official page addresses Roth conversions explicitly; treatment follows from the federal-AGI starting point.

TC-40 – Line-by-Line Instructions (2025 Utah Income Tax), Utah State Tax Commission. Utah income starts from federal AGI (TC-40 line 4), so the taxable amount of a traditional-to-Roth conversion is taxed at the flat rate with no conversion-specific relief. Checked 2026-10-12.

Capital gains

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

TC-40 – Line-by-Line Instructions (2025 Utah Income Tax), Utah State Tax Commission. Long-term capital gains enter Utah income through federal AGI and are taxed at the single flat rate; Utah has no general capital-gains exclusion. Checked 2026-10-12.
TC-40A – Supplemental Schedule Instructions (2025 Utah Income Tax), Utah State Tax Commission. The only capital-gain relief is a narrow credit for gains reinvested in a qualified Utah small business corporation, which the engine does not model. Checked 2026-10-12.
TC-40 line-by-line instructions, Utah State Tax 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 2026-10-12.
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 taxpayer credit's base includes the federal blind amount: $2,050 unmarried, $1,650 per blind married taxpayer.
The API applies these through its blind, disabled, spouse.blind and spouse.disabled fields; absent means false.

TC-40 line-by-line instructions, Utah State Tax Commission. The taxpayer-credit base is federal line 12e, which carries the blind amount as well as the aged one. Checked 2026-10-12.
Rev. Proc. 2025-32 (2026 inflation adjustments), Internal Revenue Service. The federal additional standard deduction for 2026, per condition (age 65 and blindness each count): $2,050 unmarried, $1,650 married. The state takes it where its deduction is the federal one. Checked 2026-10-12.

Part-year and nonresident returns

Part-year resident (TC-40B): the tax a full-year resident would owe on all the year's income, times the state's income ratio.
Nonresident (TC-40B): 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.
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	Utah'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, unless the couple elects separate returns; separate returns are not calculated: Utah's Special Instructions for Couples do not say which base phase-out amount of the taxpayer tax credit (TC-40 line 17, by filing status, with no row for the special filing status 9) the separate return uses.
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.

2024 Utah TC-40 Forms and Instructions (latest obtained; Wayback capture 2025-12-06 of tax.utah.gov/forms/current), Utah State Tax Commission. Part-year / nonresident return (engine 1.12.0, residency): Complete TC-40 through line 24 as if a full-year resident (flat-rate tax on Utah taxable income, less taxpayer tax credit, less APPORTIONABLE nonrefundable credits incl. retirement credit and Social Security benefits credit); TC-40B line 40 = TC-40 line 23 - line 24; Utah tax (line 41) = line 40 x line 39 ratio; carried to TC-40 line 25. Nonapportionable credits (incl. credit for tax paid to another state) then apply in full. Checked 2026-10-12.
2024 TC-40B Non and Part-year Resident Schedule (Wayback capture), Utah State Tax Commission. Part-year / nonresident return (engine 1.12.0, residency): Complete TC-40 through line 24 as if a full-year resident (flat-rate tax on Utah taxable income, less taxpayer tax credit, less APPORTIONABLE nonrefundable credits incl. retirement credit and Social Security benefits credit); TC-40B line 40 = TC-40 line 23 - line 24; Utah tax (line 41) = line 40 x line 39 ratio; carried to TC-40 line 25. Nonapportionable credits (incl. credit for tax paid to another state) then apply in full. Checked 2026-10-01.
2024 Utah TC-40 Forms and Instructions (latest obtained; Wayback capture 2025-12-06 of tax.utah.gov/forms/current), Utah State Tax Commission. Married couples whose residency differs (engine 1.13.0): Checked 2026-10-12.
Utah TC-40 2025 Forms and Instructions (Special Instructions for Married Couples, p.31), Utah State Tax Commission. Married couples whose residency differs (engine 1.13.0): Checked 2026-10-06.

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	$3,332.73
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	$5,513.46
Single, 60: $60,000 other ordinary income and a $50,000 Roth conversion	$4,895
Married filing jointly, 66: $30,000 IRA, a $40,000 Roth conversion, $30,000 Social Security ($25,500 federally taxable)	$1,890.46
Single, 58: $36,000 military retirement pay and $30,000 wages	$990.23
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	$1,276.96

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: $3,332.73

Line	Amount
Income total used by the income tests	$82,000
+ Other ordinary income in the base	$10,000
+ Social Security in the base	$15,730.34
+ Retirement income in the base	$50,000
+ Long-term gain in the base	$5,000
= State taxable income	$80,730.34
Tax from the rate schedule	$3,592.50
= Tax before credits	$3,592.50
Taxpayer tax credit	$259.77
− Credits used (never more than the tax)	$259.77
= Tax	$3,332.73

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: $5,513.46

Line	Amount
Income total used by the income tests	$144,000
+ Other ordinary income in the base	$20,000
+ Social Security in the base	$30,337.08
+ Retirement income in the base	$80,000
+ Long-term gain in the base	$10,000
= State taxable income	$140,337.08
Tax from the rate schedule	$6,245
= Tax before credits	$6,245
Taxpayer tax credit	$731.54
− Credits used (never more than the tax)	$731.54
= Tax	$5,513.46

Single, 60: $60,000 other ordinary income and a $50,000 Roth conversion: $4,895

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
= State taxable income	$110,000
Tax from the rate schedule	$4,895
= Tax before credits	$4,895
= Tax	$4,895

Married filing jointly, 66: $30,000 IRA, a $40,000 Roth conversion, $30,000 Social Security ($25,500 federally taxable): $1,890.46

Line	Amount
Income total used by the income tests	$95,500
+ Social Security in the base	$3,089.89
+ Retirement income in the base	$30,000
+ Roth conversion in the base	$40,000
= State taxable income	$73,089.89
Tax from the rate schedule	$3,252.50
= Tax before credits	$3,252.50
Taxpayer tax credit	$1,362.04
− Credits used (never more than the tax)	$1,362.04
= Tax	$1,890.46

Single, 58: $36,000 military retirement pay and $30,000 wages: $990.23

Line	Amount
Income total used by the income tests	$66,000
+ Other ordinary income in the base	$30,000
+ Retirement income in the base	$36,000
= State taxable income	$66,000
Tax from the rate schedule	$2,937
= Tax before credits	$2,937
Taxpayer tax credit	$344.77
Military retirement credit	$1,602
− Credits used (never more than the tax)	$1,946.77
= Tax	$990.23

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: $1,276.96

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
= State taxable income	$60,000
Tax from the rate schedule	$2,670
= Tax before credits	$2,670
Taxpayer tax credit	$1,393.04
− Credits used (never more than the tax)	$1,393.04
= Tax	$1,276.96

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 Utah'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
`std_deduction_single`, `std_deduction_mfj`, `std_deduction_hoh`	Tied to an indexed federal amount: the federal basic standard deduction, IRC 63(c)(2)/63(c)(7) (chained CPI-U); the increase rounded down to a multiple of $50.	These are the federal basic standard deduction amounts (IRC 63(c)(2); 2026 $16,100 single/MFS, $24,150 HOH, $32,200 joint), indexed from 2026 by the chained CPI with increases rounded down to $50 (IRC 63(c)(7)(B)(ii)). Utah's taxpayer credit is 6% of the standard deduction the claimant deducts on the federal return (59-10-1018(2)(a)(i)), so these are the federal amounts. Utah Code 59-10-1018 (Wayback copy of le.utah.gov) (Utah Legislature, statute): The credit is 6% of the federal standard deduction. Quoted: "6% of the amount the claimant deducts as allowed as". Checked 2026-09-30. 26 U.S.C. 63 (taxable income defined) (Cornell LII (U.S. Code), federal): Federal standard deduction indexing and rounding. Quoted: "the $23,625 and $15,750 amounts in subparagraph (A) shall each be increased by an amount equal to"; "such increase 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 federal standard deduction amounts. Quoted: "For taxable years beginning in 2026, the standard deduction amounts under § 63(c)(2) are as follows:". Checked 2026-10-12.
`taxpayer_credit_aged_add_single`, `taxpayer_credit_aged_add_married`, `blind_credit_base_add_unmarried`, `blind_credit_base_add_married`	Tied to an indexed federal amount: the federal additional standard deduction for age/blindness, IRC 63(f), indexed under IRC 63(c)(4) (chained CPI-U); the increase rounded down to a multiple of $50.	These are the federal additional standard deduction amounts for age 65+/blindness (IRC 63(f); 2026 $1,650 married, $2,050 unmarried), indexed under IRC 63(c)(4) by the chained CPI, increases rounded down to $50 (IRC 1(f)(7)(A)). They enter Utah's taxpayer-credit base because the federal standard deduction the claimant deducts includes them. 26 U.S.C. 63 (taxable income defined) (Cornell LII (U.S. Code), federal): 63(c)(4) indexes the subsection (f) amounts. Quoted: "each dollar amount contained in paragraph (2)(B), (2)(C), or (5) or subsection (f) shall be increased by an amount equal to". Checked 2026-10-12. 26 U.S.C. 1 (tax imposed) (Cornell LII (U.S. Code), federal): 1(f)(7)(A) rounds a 63(c)(4) increase down to $50. Quoted: "If any increase determined under paragraph (2)(A), section 63(c)(4), section 68(b)(2)". Checked 2026-10-12. Rev. Proc. 2025-32 (2026 inflation adjustments) (Internal Revenue Service, federal): 2026 amounts. Quoted: "deduction amount under § 63(f) for the aged or the blind is $1,650". Checked 2026-10-12.
`taxpayer_credit_phaseout_base_single`, `taxpayer_credit_phaseout_base_hoh`, `taxpayer_credit_phaseout_base_mfj`	Indexed: CPI as computed under IRC 1(f)(4)-(5) (12 months ending August 31), preceding calendar year over calendar year 2020; the increase rounded to the nearest $1. The engine carries the 2025 figure (the latest published) for 2026, so a projection adds 1 year of indexing at the factor's average annual rate.	59-10-1018(4)-(5): the taxpayer credit is reduced by 1.3% of state taxable income above $15,095 single / $22,643 HOH (2020 base), indexed annually by CPI (IRC 1(f)(4)-(5)) and rounded to the nearest $1; the joint amount is set to twice the single. The engine carries the TY2025 amounts. Utah Code 59-10-1018 (Wayback copy of le.utah.gov) (Utah Legislature, statute): Indexing, nearest-dollar rounding, joint = 2 x single. Quoted: "the commission shall increase or"; "decrease annually the following dollar amounts by a percentage equal to the percentage"; "round those dollar amounts listed in Subsection (5)(a) to the nearest"; "the dollar amount listed in Subsection (4)(c) is equal to the product of:". Checked 2026-09-30.
`dep_credit_base_add`	Indexed: CPI as computed under IRC 1(f)(4)-(5) (12 months ending August 31), preceding calendar year over calendar year 2020; the increase rounded to the nearest $1. The engine carries the 2025 figure (the latest published) for 2026, so a projection adds 1 year of indexing at the factor's average annual rate.	59-10-1018(1)(g) and (6): the Utah personal exemption per qualifying dependent ($1,750 base) is increased annually by CPI over calendar 2020 and rounded to the nearest $1 ($2,111 for TY2025, the engine's value). Utah Code 59-10-1018 (Wayback copy of le.utah.gov) (Utah Legislature, statute): Indexing and rounding of the personal exemption. Quoted: "$1,750 multiplied by the number"; "annually the Utah personal exemption amount listed in Subsection (1)(g) by a percentage"; "round the Utah personal exemption amount to the". Checked 2026-09-30.
`ss_exempt_agi_single`, `ss_exempt_agi_mfj`, `ss_exempt_agi_mfs`	Fixed in law: held at the rules-year amount in every later year.	59-10-1042(4): the Social Security credit is reduced by 2.5 cents per dollar of modified AGI above $45,000 MFS / $54,000 single / $90,000 HOH and joint; fixed amounts with no indexing provision. Utah Code 59-10-1042 (Wayback copy of le.utah.gov) (Utah Legislature, statute): Fixed thresholds. Quoted: "is allowed a married filing separately status, $45,000;"; "is allowed a single filing status, $54,000;"; "is allowed a joint filing status, $90,000.". Checked 2026-10-12.
`retirement_credit_per`, `retirement_credit_phaseout_single`, `retirement_credit_phaseout_mfj`, `retirement_credit_phaseout_mfs`	Fixed in law: held at the rules-year amount in every later year.	59-10-1019: $450 per eligible claimant, reduced by 2.5 cents per dollar of modified AGI above $16,000 MFS / $25,000 single / $32,000 HOH and joint; fixed amounts. Utah Code 59-10-1019 (Wayback copy of le.utah.gov) (Utah Legislature, statute): Fixed credit and thresholds. Quoted: "may claim a nonrefundable tax credit of $450 against taxes otherwise due under this part"; "allowed a married filing separately status,"; "$16,000;"; "allowed a single filing status, $25,000;". Checked 2026-10-12.
`retirement_credit_min_age`	Birth-year cutoff (born in 1952 or earlier): age 74 in 2026, one year older each later year.	An eligible claimant is one born on or before December 31, 1952, so the qualifying age rises one year per tax year (74 in 2026) and no newly aging retiree ever qualifies. Utah Code 59-10-1019 (Wayback copy of le.utah.gov) (Utah Legislature, statute): Birth-date cutoff. Quoted: "born on or before December 31, 1952.". Checked 2026-10-12.
`dep_child_credit`, `dep_child_credit_threshold_single`, `dep_child_credit_threshold_mfj`, `dep_child_credit_threshold_mfs`	Fixed in law: held at the rules-year amount in every later year.	59-10-1047: $1,000 per qualifying child, reduced by 10 cents per dollar of modified AGI above $30,500 MFS / $49,000 single and HOH / $61,000 joint; fixed amounts. Utah Code 59-10-1047 (Wayback copy of le.utah.gov) (Utah Legislature, statute): Fixed credit and thresholds. Quoted: "a claimant may claim a nonrefundable tax credit of $1,000 for each qualifying child."; "is allowed a married filing separately status, $30,500;"; "filing status or head of household filing status, $49,000; and"; "is allowed a joint filing status, $61,000.". Checked 2026-09-30.
`dep_child_credit_max_age`	Attained age: the same age in every year.	A qualifying child must be under six on the last day of the taxable year (engine: 5 or younger): a fixed age. Utah Code 59-10-1047 (Wayback copy of le.utah.gov) (Utah Legislature, statute): Under six. Quoted: "who is under six years old on the last day of the claimant's taxable year.". Checked 2026-09-30.
`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

The retirement credit (born on or before 1952) replaces the Social Security and military credits when it is the larger, since the form allows one or the other per return.
The taxpayer-credit phase-out bases are the 2025 amounts ($18,213 / $36,426 / $27,320); 2026's indexed amounts are not yet published.
The military retirement credit uses the 2026 rate of 4.45% by inference from the 2025 worksheet (0.045 = the 2025 rate); the 2026 text of 59-10-1043 was not fetched.
The at-home parent credit (per child 12 months or younger, for a parent at home with little earned income and a federal AGI under the limit; TC-40A code 01) is not calculated: whether a parent provides full-time care at home is not an input. Sources: Utah Code 59-10-1018. Definitions -- Nonrefundable taxpayer tax credits (effective 1/1/2026) (checked 2026-10-05); TC-40 – Line-by-Line Instructions (2025 Utah Income Tax) (checked 2026-10-12); IRS releases tax inflation adjustments for tax year 2026, including amendments from the One, Big, Beautiful Bill (checked 2026-10-12); Rp 25 32 (checked 2026-10-12); IRS releases tax inflation adjustments for tax year 2026 (checked 2026-10-12); Utah State Legislature: C59-10-S1047_2026050620260506.html (checked 2026-09-28); Utah Individual Income Tax: TC-40A credits (Earned Income Tax Credit, code AM, UCA 59-10-1044), tax year 2025 (checked 2026-10-12).
Married couples whose residency differs (engine 1.13.0): when one spouse is a full-year resident and the other a nonresident, separate returns are not calculated: Utah's Special Instructions for Couples do not say which base phase-out amount of the taxpayer tax credit (TC-40 line 17, by filing status, with no row for the special filing status 9) the separate return uses. Sources: 2024 Utah TC-40 Forms and Instructions (latest obtained; Wayback capture 2025-12-06 of tax.utah.gov/forms/current) (checked 2026-10-12); 2024 TC-40B Non and Part-year Resident Schedule (Wayback capture) (checked 2026-10-01); 2024 Utah TC-40 Forms and Instructions (latest obtained; Wayback capture 2025-12-06 of tax.utah.gov/forms/current) (checked 2026-10-12); Utah TC-40 2025 Forms and Instructions (Special Instructions for Married Couples, p.31) (checked 2026-10-06).

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 Scenarios replay the TC-40 tax and taxpayer tax credit lines 9-22 and the TC-40A Social Security (AH) and military retirement (AJ) credit worksheets, 2025 forms with the 2026 rate and federal deductions; tests/test_state_worksheets_3.c.

Golden scenarios (hand-computed expected tax, asserted to within $1): none for this state.
State-specific unit tests: test_ss_taxing_state_includes_ss, test_ut_hoh_uses_mfj_ss_threshold, test_v3_folds_v2, test_ut_taxpayer_credit_and_mfs_ss, test_ut_rn, test_compute_federal_ss_parts, test_applied, test_legacy_request_equals_v2, test_ut_military_credit, test_ut_credit_includes_aged_amount, test_hoh_and_credit_gaps, test_ut_retirement_credit.
Structural tests covering every state: 7.
State forms and worksheets followed in the test derivations: TC-40 lines 9-10 and taxpayer tax credit lines 12, 16-20, 22; TC-40A code AH Social Security Benefits Credit worksheet (lines 1-13); TC-40A code AJ Military Retirement Credit worksheet; TC-40A code 18 Retirement Credit worksheet.