Illinois pairs a simple flat income tax with a large, diversified economy anchored by Chicago, manufacturing, and agriculture. Median household income often tracks close to national averages. Tax conversations in Illinois frequently highlight high property taxes and pension funding pressures; the income tax itself is a flat 4.95% without graduated brackets. This page estimates federal tax, a simplified Illinois line, and FICA so you can benchmark take-home pay — not a substitute for Form IL-1040.
2025 federal + simplified state + FICA — updates as you type.
Illinois personal exemptions and Schedule CR credits are not modeled. State tax applies the JSON flat rate to federal taxable income in this tool.
Not applied in this simplified model (no credits). For illustration only.
State tax uses a flat effective rate on taxable income — not your actual state brackets. FICA: Social Security 6.2% on wages up to $176,100 and Medicare 1.45% on all wages shown.
SS $4,650.00 · Medicare $1,087.50
Federal 22.00% + state 4.95%
Estimated take-home
$58,179 / yr
$4,848 / month
Federal brackets (2025 · Single)
Rate from data/rates/us-tax-brackets.json → stateRates.IL. No graduated brackets in that file.
| Component | Rate / rule in app data |
|---|---|
| State individual income tax | Flat 4.95% (0.0495) |
| Bracket structure | None — single flat rate |
Using this site’s engine: 2026 federal brackets and standard deduction from the JSON file, no 401(k)/IRA/HSA, state tax = flat rate × federal taxable income. "Fed + state" = (federal + state) ÷ gross. "Total w/ FICA" includes Social Security and Medicare.
| Gross income | Fed + state effective | Total w/ FICA |
|---|---|---|
| $50,000 | ~11.4% | ~19.0% |
| $100,000 | ~17.8% | ~25.5% |
Illinois uses a flat rate rather than multiple state brackets. Personal exemptions are an important part of the return — often cited around $2,425 per exemption under recent law (verify current year amounts with the Illinois Department of Revenue). Property taxes are high in many Illinois counties; that affects housing costs but is separate from state income tax withholding on wages.
Illinois imposes a flat individual income tax rate of 4.95% on Illinois base income under current law. This site’s calculator reads that rate from its 2026 `us-tax-brackets.json` state rate table and applies it in simplified form to federal taxable income (after the federal standard deduction in the tool) — not a full IL-1040 simulation.
Most retirement distributions (pensions, 401(k), traditional IRA withdrawals) are generally subject to Illinois income tax, though Illinois excludes certain income types (e.g. eligible retirement income under state rules). Roth qualified distributions and Social Security treatment depend on federal and state rules — confirm with Illinois Department of Revenue guidance or a tax professional.
A single flat rate is simpler than progressive states like California or New York, but 4.95% on a broad base can still mean meaningful state tax versus no-tax states like Florida or Texas. Border states Wisconsin, Iowa, Missouri, Indiana, and Kentucky each use different brackets or flat rates — run the same income in the all-states US tool to compare.
Illinois does not mirror the federal standard deduction for state tax in the same way Georgia does. Instead, Illinois filers typically rely on personal exemptions (commonly cited around $2,425 per exemption for recent tax years under state law). This calculator does not model Illinois exemptions line-by-line; it uses a flat 4.95% on simplified taxable income for illustration.
If you are an Illinois resident, you generally file Illinois and report worldwide income subject to Illinois rules. If you live in another state but work for an Illinois employer, or vice versa, apportionment and reciprocal agreements may apply. Remote work has made multi-state situations common — use official residency rules or a CPA when states disagree.
For calendar-year filers, Illinois individual income tax returns are typically due April 15 following the tax year (or the next business day if April 15 falls on a weekend or holiday), aligning with the federal due date unless extended. Extensions to file may not extend time to pay tax due.
Educational estimates only. Not IRS or Illinois Department of Revenue advice.