Illinois charges a single flat-rate state income tax — the same percentage regardless of how much you earn — on top of federal tax and FICA. The calculator above applies the 2025 federal brackets, the Illinois flat rate and FICA to show your take-home pay.

Illinois's flat tax

Unlike progressive states such as California or New York, Illinois taxes nearly all income at one flat rate (around 4.95%). That makes the state-tax portion of your deductions simple and predictable: the same percentage applies whether you earn $40,000 or $400,000.

What it means for take-home

A flat tax makes Illinois comparatively cheaper than a progressive state at high incomes and comparatively more expensive at low incomes, where progressive states tax the first dollars lightly. Combined with federal tax and FICA, the flat rate gives Illinois a middle-of-the-pack take-home — more than high-tax California, less than no-tax Texas or Florida.

Frequently asked questions

How much is take-home pay on $80,000 in Illinois?
A $80,000 gross salary in Illinois works out to $60,843 take-home per year, or $5,070 per month. That is an effective tax rate of 23.9% across the 2025 federal + state bands.
What is the federal standard deduction (single) for 2025?
United States's federal standard deduction (single) for 2025 is $15,000. Annual earnings up to that threshold are not subject to income tax.
How does Illinois tax compare to other US states?
Illinois has a flat 4.95% state income tax — no brackets, applied to AGI above the personal exemption. Simpler to forecast than progressive-tax states but no upper-band relief.
How often do Illinois and federal tax rates change?
IRS publishes federal brackets, the standard deduction, and FICA wage bases each November for the following tax year. The bracket boundaries move with the Chained CPI; the top rate (37%) has been stable since 2018. State income-tax brackets change on independent legislative calendars — California, New York, and Illinois have annual indexing; Texas and Florida do not levy a state income tax.
What is covered by this take-home pay calculator?
Single filer, five US states live in 2025: California, New York, Texas, Florida, Illinois. Federal income tax + FICA (6.2% Social Security up to the wage base, 1.45% Medicare with no cap, +0.9% Additional Medicare above $200,000) + state income tax where applicable. Pre-tax 401(k), HSA, and itemised deductions above the standard are not yet modeled.