What's the difference between marginal and effective tax rate in Illinois?

Marginal rate = the rate applied to your next dollar of income. Effective rate = total tax paid ÷ total gross income. In states with graduated brackets like California or New York, marginal can run 8-10% while effective at $100K is 4-6%. Illinois's structure: 4.95% flat (2026) — see the income-tier reference table on this page for effective rate at each tier.

Are local / city taxes included in this Illinois paycheck calculator?

The headline take-home figure includes federal + state + FICA. Local taxes (city, county, municipal occupational, school district) are not applied to the headline number but are flagged separately for the eight states where they materially change take-home: NY (NYC, Yonkers), PA (Philly, Pittsburgh), MI (Detroit + 22 cities), OH (RITA / CCA cities), KY (most counties), MD (all counties), IN (all counties), and AL (Birmingham, Macon, Bessemer).

What state taxes does Illinois apply to wages?

Illinois's state income tax structure is: 4.95% flat (2026) . State standard deduction and personal exemption rules differ from federal — see the methodology page for the exact figures applied to the calculator on this page.

What about HSA, dependent care, or transit benefits in Illinois?

HSA contributions are pre-tax federally and FICA-exempt (one of the few benefits that reduces FICA), and pre-tax in most states except California and New Jersey (which tax HSA at the state level). Dependent Care FSA up to $5,000/year is pre-tax federally and state in most jurisdictions. Transit/parking benefits up to $315/month (2026) are pre-tax federally. The page calculator doesn't model these — apply them as pre-tax adjustments to gross.

Does Illinois tax bonuses differently from regular paychecks?

Federal supplemental withholding on bonuses defaults to a flat 22% (or 37% above $1M annual). Illinois state withholding follows the state's supplemental rules: some states use the regular bracket; others use a flat supplemental rate. Year-end your actual tax liability is identical regardless of withholding method — the difference is whether you owe / refund at filing.

Why doesn't Illinois use brackets like California or New York?

Flat-rate state taxes are politically and administratively simpler — one rate, no brackets to update annually, easier withholding, smaller compliance burden for employers. The trade-off is regressive distribution at low incomes (a flat 4-5% tax on a $30K wage is a heavier burden than the same percentage on $200K). About a dozen U.S. states have moved to or maintained flat-rate structures.

Does Illinois's flat tax apply to capital gains, dividends, retirement income?

Illinois flat-rate state tax generally applies to most W-2 wages, self-employment income, and ordinary investment income. Treatment of pensions, Social Security, IRA distributions, and capital gains varies — most flat-tax states tax these at the same flat rate as wages, but exceptions exist (e.g., PA exempts most retirement income from state tax entirely; IL exempts retirement). The calculator on this page applies to W-2 wage income.

Illinois Take-Home Pay Calculator — 2026 Federal/State/FICA Stack

TL;DR — Illinois take-home

The Illinois state-tax structure is flat-rate (no brackets), which means a raise from $80K to $200K is taxed at the same state percentage at the margin. Federal + state + FICA on $100K = $74,153.

BEA RPP 98.8 for Illinois is near the 100 baseline; real take-home ($75,090) is within a few percent of nominal take-home ($74,153).

Reference take-home table — Illinois (2026, single filer)

Gross W-2	Federal	State	FICA	Take-home	Effective rate
$40,000	$2,662	$1,980	$3,060	$32,298	19.3%
$60,000	$5,062	$2,970	$4,590	$47,378	21.0%
$80,000	$8,847	$3,960	$6,120	$61,073	23.7%
$100,000	$13,247	$4,950	$7,650	$74,153	25.8%
$130,000	$20,018	$6,435	$9,945	$93,602	28.0%
$160,000	$27,218	$7,920	$12,240	$112,622	29.6%
$200,000	$36,818	$9,900	$14,283	$138,999	30.5%

Standard deductions ($15,750 federal + state-specific 2026 figure) applied before bracket math. FICA = SS 6.2% to $183,600 + Medicare 1.45% (+0.9% above $200K). Local taxes (city/county) not in headline numbers.

How Illinois taxes work — 2026 structure

Flat-rate state income tax — same rate at every income tier

Illinois uses a flat-rate state income tax: 4.95% flat (2026). The flat-rate model means your effective and marginal state-tax rates are identical at every income tier — a simplification compared with graduated states.

The state's 2026 standard deduction is applied before the flat rate. FICA stack is the same as everywhere else (SS + Medicare). Local-tax overlay applies on top of state in some jurisdictions — see the local section below if applicable.

Real take-home — Illinois cost of living adjusted

Metric	Illinois value
BEA Regional Price Parity (all-items, 2023)	98.8 (US = 100)
RPP — goods	101.6
RPP — rents	92.4
RPP — services	80.4
$100K gross take-home (nominal)	$74,153
Real take-home (purchasing power)	$75,090

Illinois's overall RPP (98.8) tracks close to the national 100 baseline, so nominal and real take-home stay close — both around the $74,153 mark.

Compared with Illinois's neighbors at $100K gross

State	$100K take-home	Effective rate	Page
Illinois (this page)	$74,153	25.8%	—
Indiana	$76,203	23.8%	Indiana paycheck →
Wisconsin	$74,891	25.1%	Wisconsin paycheck →
Iowa	$75,902	24.1%	Iowa paycheck →
Missouri	$75,069	24.9%	Missouri paycheck →

Same single-filer assumptions across all rows. Federal + state + FICA only — local taxes not applied here.

Frequently asked — Illinois paycheck

What's the difference between marginal and effective tax rate in Illinois?: Marginal rate = the rate applied to your next dollar of income. Effective rate = total tax paid ÷ total gross income. In states with graduated brackets like California or New York, marginal can run 8-10% while effective at $100K is 4-6%. Illinois's structure: 4.95% flat (2026) — see the income-tier reference table on this page for effective rate at each tier.
Are local / city taxes included in this Illinois paycheck calculator?: The headline take-home figure includes federal + state + FICA. Local taxes (city, county, municipal occupational, school district) are not applied to the headline number but are flagged separately for the eight states where they materially change take-home: NY (NYC, Yonkers), PA (Philly, Pittsburgh), MI (Detroit + 22 cities), OH (RITA / CCA cities), KY (most counties), MD (all counties), IN (all counties), and AL (Birmingham, Macon, Bessemer).
What state taxes does Illinois apply to wages?: Illinois's state income tax structure is: 4.95% flat (2026). State standard deduction and personal exemption rules differ from federal — see the methodology page for the exact figures applied to the calculator on this page.
What about HSA, dependent care, or transit benefits in Illinois?: HSA contributions are pre-tax federally and FICA-exempt (one of the few benefits that reduces FICA), and pre-tax in most states except California and New Jersey (which tax HSA at the state level). Dependent Care FSA up to $5,000/year is pre-tax federally and state in most jurisdictions. Transit/parking benefits up to $315/month (2026) are pre-tax federally. The page calculator doesn't model these — apply them as pre-tax adjustments to gross.
Does Illinois tax bonuses differently from regular paychecks?: Federal supplemental withholding on bonuses defaults to a flat 22% (or 37% above $1M annual). Illinois state withholding follows the state's supplemental rules: some states use the regular bracket; others use a flat supplemental rate. Year-end your actual tax liability is identical regardless of withholding method — the difference is whether you owe / refund at filing.
Why doesn't Illinois use brackets like California or New York?: Flat-rate state taxes are politically and administratively simpler — one rate, no brackets to update annually, easier withholding, smaller compliance burden for employers. The trade-off is regressive distribution at low incomes (a flat 4-5% tax on a $30K wage is a heavier burden than the same percentage on $200K). About a dozen U.S. states have moved to or maintained flat-rate structures.
Does Illinois's flat tax apply to capital gains, dividends, retirement income?: Illinois flat-rate state tax generally applies to most W-2 wages, self-employment income, and ordinary investment income. Treatment of pensions, Social Security, IRA distributions, and capital gains varies — most flat-tax states tax these at the same flat rate as wages, but exceptions exist (e.g., PA exempts most retirement income from state tax entirely; IL exempts retirement). The calculator on this page applies to W-2 wage income.

Sources & methodology

Federal brackets — IRS Rev. Proc. 2025-32, 2026 single-filer tables, $15,750 standard deduction.
Illinois state brackets — 2026 Illinois Department of Revenue / Tax Foundation 2026 individual income tax structure summary. State standard deduction applied where relevant.
FICA — Social Security 6.2% on wages up to the 2026 wage base of $183,600; Medicare 1.45% on all wages; +0.9% Additional Medicare on wages above $200K (single filer).
BEA Regional Price Parities — 2023 vintage (all-items, goods, services, rents).
See the methodology · tax for full computation details and limitations.

By Marcus Liang · Founder & Editor · Last synced 2026-05-05.

Cross-state comparison: see how Illinois take-home ranks against the other 50 paycheck calculators on the Real Wage Atlas → — four-way ranking by real wage, after-tax take-home, state-tax savings, and cost-of-living arbitrage.