Illinois vs Arizona: state income tax, 2025
For reference household P1 (single, $60,000 of wages), Illinois charges $2,829or less and Arizona charges $1,106or less. Both are bounded in the same direction, so the difference between them cannot be stated.
Both figures are a hypothetical full-year resident return for tax year 2025, over the same federal return, and count state income tax only. Neither is a relocation estimate: moving mid-year means two part-year returns, which this site does not figure. “Or less” means a mechanism the engine does not yet model would lower the figure; “or more” that it would raise it.
Six households, both states
| Household | Illinois | Arizona | Illinois minus Arizona |
|---|---|---|---|
| P1 Single, $60,000 of wages | $2,829or less | $1,106or less | not bounded |
| P2 Married filing jointly, $150,000, two children | $6,861or less | $2,763or less | not bounded |
| P3 Single, $85,000 wages + $15,000 long-term gain + $3,000 qualified dividends | $4,957or less | $2,181or less | not bounded |
| P4 Married retirees, $40,000 Social Security + $30,000 pension + $20,000 IRA, both 65+ | $0or less | $358or less | not bounded |
| P5 Head of household, $45,000, one child | $1,945or less | $434or less | not bounded |
| P6 Single, $1,200,000 of wages + $500,000 long-term gain | $84,150or less | $42,106or less | not bounded |
Full-year resident figures for 2025, state income tax only, with the same federal return in every column. Every figure is provisional. “Not shown” and “not figured” mean the engine will not state a number it cannot stand behind; hover for why.
Where the difference comes from
Illinois
- Where the return starts. Starts from federal adjusted gross income.
- Rate. A flat 4.95% on taxable income.35 ILCS 5/201; 2025 Form IL-1040 Instructions: "The Illinois income tax rate is 4.95 percent (.0495)." (checked 2026-08-05)
- Personal exemption. $2,850 per filer and $2,850 per dependant.35 ILCS 5/204; 2025 Form IL-1040 Instructions: "The personal exemption amount for tax year 2025 is $2,850." Line 10b and 10c each add $1,000 per box checked for age 65 or over and for blindness. (checked 2026-08-05)
- Excluded from income. Retirement income.2025 Form IL-1040 Instructions, Line 5: subtract federally taxed Social Security and retirement income from qualified employee benefit plans, IRAs and self-employed retirement plans reported on federal Form 1040 lines 4b and 5b, and Social Security and railroad retirement reported on line 6b. (checked 2026-08-05)
- Added to income. Municipal bond interest from other states.2025 Form IL-1040 Instructions, Line 2: add the federally tax-exempt interest and dividend income reported on federal Form 1040 line 2a. (checked 2026-08-05)
- Earned income credit. 20% of the federal credit, refundable.
Arizona
- Where the return starts. Starts from federal adjusted gross income.
- Rate. A flat 2.5% on taxable income.A.R.S. §43-1011; 2025 Arizona Form 140 instructions, line 46: "Multiply line 45 by 2.5% (.025) and enter the result." (checked 2026-08-05)
- Standard deduction. $15,750 single, $31,500 married filing jointly.A.R.S. §43-1041; 2025 Form 140 instructions, "Your Standard Deduction": $15,750 single, $31,500 married filing joint, $15,750 married filing separate, $23,625 head of household. Arizona conforms to the federal amounts. Box 5: "You may file as head of household on your Arizona return only if … You qualify to file as a qualifying widow or widower on your federal return." (checked 2026-10-20)
- Excluded from income. Social Security benefits.2025 Form 140 instructions, line 30: "Arizona does not tax … Social security benefits received under Title II of the Social Security Act." The federally included amount is subtracted. (checked 2026-08-05)
What this comparison leaves out
Mechanisms the engine does not model yet. Each one is named with the direction it would move the figure, which is where every “or less” above comes from.
Illinois
- Property tax and K-12 education expense credits (Schedule ICR) 35 ILCS 5/208, 5/201(m) — the figure is too high without it
- Illinois municipal bond and U.S. obligation subtractions (Schedule M) 35 ILCS 5/203(a)(2) — the figure is too high without it
- Credit for tax paid to another state (Schedule CR) 35 ILCS 5/601(b)(3) — the figure is too high without it
Arizona
- Charitable contribution carryover from a prior year on the increased standard deduction (page 3, line 3C) where no 2025 gift is recorded A.R.S. §43-1041 — the figure is too high without it
- Government pension exclusion (line 29a) and uniformed-services pay (line 29b) A.R.S. §43-1022(2), (3) — the figure is too high without it
- Other exemptions (line 40) and qualifying parents and grandparents (line 41) A.R.S. §43-1023 — the figure is too high without it
- Dependants aged under 17 who do not qualify for the federal child tax credit A.R.S. §43-1073.01 — the figure is too high without it
- Arizona Schedule A line 5: mortgage interest equal to a federal mortgage credit certificate credit (Form 8396) A.R.S. §43-1042 — the figure is too high without it
- Net long-term capital gain subtraction for assets acquired after 2011 (lines 23–24); a gain whose acquisition date is not shown, such as a 1099-DIV distribution, takes none A.R.S. §43-1022 — the figure is too high without it
- Interest on U.S. obligations (line 28) A.R.S. §43-1022 — the figure is too high without it
- Active-service pay of the armed forces, reserves and National Guard (line 32) and 529 / ABLE contributions (line 34) A.R.S. §43-1022 — the figure is too high without it
- Nonrefundable credits from Form 301 (line 51), e.g. qualifying charitable, foster care, public school and school tuition organization contributions A.R.S. §§43-1088, 43-1089, 43-1089.01 — the figure is too high without it
- Increased excise tax credit (line 56) and property tax credit (line 57, Form 140PTC) A.R.S. §§43-1072, 43-1072.01 — the figure is too high without it
- Credit for taxes paid to another state or country (Form 309) A.R.S. §43-1071 — the figure is too high without it
Taxes that are not income tax. Property tax, sales and excise taxes, and state payroll levies such as disability or paid-leave contributions are not counted here, and none of them is small. Federal tax is excluded because it is the same in both columns. A state income tax comparison is not a total tax burden comparison; see methodology.
Data status
Illinois. 2025 rules are provisional; engine coverage is implemented, with 3 mechanisms declared as not yet modelled. See the 2025 rate table.
Arizona. 2025 rules are provisional; engine coverage is implemented, with 11 mechanisms declared as not yet modelled. See the 2025 rate table.
2026 state rules are not built yet, so this page compares 2025 only. Track status on the 2025 data status board.
Try it with your own return
The six households above are reference cases. Your own return will land differently. Compare Illinois and Arizona over your own return — it stays in your browser.