Illinois · State Income Tax Deduction
State Income Tax Deduction in Illinois (2026)
Deduct state and local income taxes, or sales taxes, as part of the federal SALT itemized deduction. Illinois has a flat 4.95% income tax, so a Illinois filer's combined marginal rate on the next dollar at $72,205 of income is about 26.95% (22% federal + 4.95% IL).
2026 savings example for Illinois
Planning estimate for a single filer earning $72,205 (Illinois median household income in LevyIO's state dataset) who removes $5,000 from taxable income. Federal tax uses the 2026 IRS brackets after the $16,100 standard deduction; IL tax uses the state brackets in LevyIO's dataset and assumes the state follows the federal treatment.
Estimated total savings
$1,348
Federal savings
$1,100
$7,055 → $5,955 · 22% bracket
IL state savings
$248
$3,429 → $3,182 · 4.95% marginal
Combined marginal rate
26.95%
≈ $270 saved per $1,000 deducted
Statutory maximum for this item in LevyIO's dataset: $40,400.
Federal × Illinois marginal rates (2026, single)
Gross-income ranges include the federal standard deduction. The IL column is the state marginal rate at the midpoint of each range. The last column is the tax saved per $1,000 deducted at that combined rate.
| Federal bracket | Gross income (single) | IL marginal | Combined | Per $1,000 |
|---|---|---|---|---|
| 10% | $16,100 - $28,500 | 4.95% | 14.95% | $150 |
| 12% | $28,500 - $66,500 | 4.95% | 16.95% | $170 |
| 22% | $66,500 - $121,800 | 4.95% | 26.95% | $270 |
| 24% | $121,800 - $217,875 | 4.95% | 28.95% | $290 |
| 32% | $217,875 - $272,325 | 4.95% | 36.95% | $370 |
| 35% | $272,325 - $656,700 | 4.95% | 39.95% | $400 |
| 37% | Over $656,700 | 4.95% | 41.95% | $420 |
Eligibility & forms
Taxpayers who itemize and deduct state/local income taxes or general sales taxes on Schedule A
- Part of the combined SALT cap
- Must itemize
- Choose income taxes OR sales taxes, not both
- Property taxes share the same overall SALT limit
Federal forms: Schedule A
Illinois filing notes
Illinois has no broad standard deduction, but the 2026 personal exemption reduces Illinois net income before the 4.95% rate. Verify retirement subtractions on Publication 120, claim Schedule ICR property-tax and K-12 credits when eligible, and use reciprocity rules for IA/KY/MI/WI wage cases.
Common mistakes: Double-counting property tax in SALT; Not considering sales tax alternative; Assuming the federal SALT deduction also reduces state taxable income.
Frequently asked questions
How much can the State Income Tax Deduction save a Illinois taxpayer in 2026?
In LevyIO's example, a single filer with $72,205 of income (the Illinois median household income in our state dataset) who removes $5,000 from taxable income saves about $1,100 in 2026 federal tax (22% marginal bracket) plus about $248 in Illinois tax (4.95% state marginal rate), roughly $1,348 combined. It is a planning estimate computed from the 2026 IRS brackets and LevyIO's IL bracket data, not a survey figure.
What is the Illinois income tax rate for 2026?
Illinois has a flat 4.95% income tax. The IL standard deduction in LevyIO's dataset is $2,925 single / $5,850 married. Flat 4.95% on Illinois net income. No standard deduction, but tax year 2026 uses a $2,925 personal exemption per taxpayer before the rate applies. Most retirement income is subtractable.
Who qualifies for the State Income Tax Deduction in Illinois?
Taxpayers who itemize and deduct state/local income taxes or general sales taxes on Schedule A. The federal rules are the same in every state; the requirements are: Part of the combined SALT cap; Must itemize; Choose income taxes OR sales taxes, not both; Property taxes share the same overall SALT limit. Illinois filers should confirm on the IL return whether the state follows the federal treatment.
Which forms do I file to claim the State Income Tax Deduction?
Federal: Schedule A. Illinois: check the Illinois Department of Revenue instructions for the matching state schedule. Common mistakes: Double-counting property tax in SALT; Not considering sales tax alternative; Assuming the federal SALT deduction also reduces state taxable income.
State Income Tax Deduction in other states
Sources
Reviewed 2026-09-17. Estimates are educational planning figures computed from the IRS 2026 inflation adjustments and LevyIO's state bracket dataset; they are not tax advice.