Illinois Paycheck Calculator

Illinois has taxed wages at a single flat rate since July 1, 2017: 4.95%, applied identically whether taxable income is $20,000 or $2 million. This is a direct consequence of the Illinois Constitution, which requires the state's individual income tax to be non-graduated — a 2020 ballot measure asking voters to allow graduated rates failed, so the flat structure remains and any change would need a fresh constitutional amendment, not just new legislation.

Rather than a standard deduction, Illinois reduces taxable income through a flat personal exemption: $2,925 per person for tax year 2026, up from $2,850 in 2025, an inflation adjustment the state makes most years even though the 4.95% rate itself hasn't moved since 2017. A married couple filing jointly claims one exemption per spouse — $5,850 total — which is arithmetic, not a separately legislated joint figure the way New York's married standard deduction is.

The worked example above shows what that means in practice: a single filer earning $75,000 pays 4.95% on $72,075 (gross minus the $2,925 exemption), for $3,567.71 in state tax, while an identical married filer pays 4.95% on $69,150 (gross minus the $5,850 married exemption), for $3,422.93 — a $144.78 difference driven entirely by the exemption, since the rate itself never changes.

Because there are no brackets, Illinois's state-tax math is simpler than New York's or the federal system's — the only moving part is which exemption amount applies, not a schedule of rates that changes as income rises.

Illinois's personal exemption is not unconditional at every income level. It phases out completely for taxpayers whose federal adjusted gross income exceeds $250,000 (single, married filing separately, or head of household) or $500,000 (married filing jointly) — a cliff, not a gradual reduction, once AGI crosses the threshold, according to the Illinois Department of Revenue's own guidance for the exemption.

This calculator's underlying engine has no phase-out concept built in: its flat-tax variant applies one exemption figure at every income level, the same simplifying assumption it uses for every other flat-rate state. That is a fine approximation for the overwhelming majority of Illinois earners, since $250,000/$500,000 AGI is well above a typical wage, but it means this calculator's result for someone above that threshold is not accurate — it will show a lower Illinois tax bill than that person actually owes, because the tool keeps subtracting an exemption the law has already eliminated for them.

Anyone whose adjusted gross income is near or above $250,000 (single) or $500,000 (married) should treat this calculator's output as an underestimate of their real Illinois tax liability and consult the Department of Revenue's own guidance, a tax professional, or Illinois's Schedule NR/IL-1040 instructions directly rather than relying on this page's number. For the large majority of users well below those thresholds, the calculator's exemption math is exact.

This page computes statutory federal, Illinois state, and FICA withholding on a regular annual salary using the 2026 personal exemption and flat 4.95% rate — the same core structure every state page in this series uses, adapted to Illinois's specific exemption-instead-of-deduction mechanic. It does not account for Illinois property tax credits, the state's earned income credit, pre-tax retirement or health contributions, or any other credit or deduction that could change a real return's bottom line.

Illinois residents who also work in a different state, or who have significant non-wage income, should treat this figure as a starting estimate rather than a final answer — reciprocal-agreement rules and multi-state withholding are both out of scope for a single-state paycheck calculator built around one salary and one filing status.

As with every state page in this series, the number that matters most for comparing states is not the headline rate but the combination of rate and exemption/deduction actually applied — Illinois's 4.95% flat rate with a modest exemption produces a materially different bill than Pennsylvania's lower 3.07% flat rate with no exemption at all, even before either state's local taxes (which Illinois, unlike Pennsylvania, does not generally impose on wages) are considered.