Illinois Paycheck Calculator

How Illinois paychecks are calculated

An Illinois paycheck is built in four steps, and only one of them is state income tax. Start with gross pay — an annual salary, or an hourly rate multiplied by your weekly hours across 52 weeks. Subtract your pre-tax elections: traditional 401(k) or 403(b) contributions, HSA contributions, and your share of employer health, dental, or vision premiums. What remains is close to both your federal adjusted gross income and your Illinois adjusted gross income, because Illinois starts its calculation at the federal one.

Federal income tax then applies the 2026 brackets to federal taxable income, which is AGI less the standard deduction. FICA is calculated on gross wages — pre-tax retirement and HSA contributions do not reduce it — at 6.2% for Social Security up to $184,500 and 1.45% for Medicare on every dollar. Illinois comes last: your withholding allowances come off wages and 4.95% applies to the remainder.

Everything here runs client-side in your browser. The 2026 figures the Department of Revenue published in Booklet IL-700-T are baked into the code that recalculates on every keystroke, so there is no submit button, no account, and no data leaves your device.

Illinois income tax rate

Illinois taxes individual income at a flat 4.95% rather than running a bracket system. That puts it with Michigan and Indiana, its two flat-rate neighbors, and against California, New York, Wisconsin, and Minnesota, which all step through multiple tiers. In Illinois the rate is the same for single filers, joint filers, heads of household, and married filing separately. The 2026 withholding booklet confirms it is unchanged from the prior year. Illinois voters also wrote a flat-rate requirement into the state constitution in 2022, when Proposition 42 passed and made any graduated or higher-rate income tax dependent on three-fifths approval in both chambers or a statewide referendum. One more thing worth knowing: Illinois taxes investment income — interest, dividends, capital gains — at the same 4.95% it applies to wages.

Illinois withholding allowances

Illinois withholding is driven by Form IL-W-4, the Employee's and Other Payee's Illinois Withholding Allowance Certificate. It is a separate form from your federal W-4 and it is not replaced by it — an employee who claims total exemption on the federal W-4 can still owe and still have Illinois tax withheld. Each allowance you claim removes $2,925 from annual wages in 2026, up from $2,850 the year before. Because Illinois uses a flat rate, the value of an allowance is identical for a low earner and a high one — $145 of tax per allowance — which is not true in graduated-rate states.

The allowance is an annual figure, so the per-paycheck value depends on how often you are paid. The table below is generated by the same engine that powers the calculator.

Source: Illinois Department of Revenue, Booklet IL-700-T, 2026.

High-income exemption limits

The Illinois exemption allowance disappears entirely at high incomes. Per the Department of Revenue's IL-1040 exemption allowance chart, if you are married filing jointly and your federal adjusted gross income is greater than $500,000, you are not entitled to an exemption allowance — enter zero. The threshold is $250,000 for single, head of household, married filing separately, and qualifying surviving spouse filers. This is a cliff rather than a gradual phase-out, so crossing it costs a household several thousand dollars of tax in a single step.

Every figure computed by the engine above — none of these numbers were typed in by hand.

Illinois paycheck deductions

Illinois adds no state-run payroll premium of its own. There is no state disability insurance and no state-funded paid family leave contribution, unlike Washington, California, or New York. The Paid Leave for All Workers Act guarantees job-protected leave but is unpaid, so nothing extra appears on the pay stub for it. Unemployment insurance is funded by Illinois employers, not employees. That means the only state-level income deduction on an Illinois paycheck is the 4.95% tax itself.

Federal income tax and FICA

Federal tax is the largest deduction for most Illinois workers, and it is the only genuinely progressive layer in the stack. The 2026 brackets below apply after the federal standard deduction — $16,100 single, $32,200 married filing jointly, $24,150 head of household — plus $2,050 per qualifying factor for age 65 or older or blind.

FICA is separate from income tax and applies to virtually all wages. Social Security takes 6.2% up to the $184,500 wage base for 2026, which is why the effective rate falls as the year goes on for higher earners. Medicare takes 1.45% with no cap, plus an additional 0.9% above $200,000 single or $250,000 joint. Social Security, Medicare, and the additional Medicare tax are all deducted before your Illinois figure on this page.

Weekly, bi-weekly, semi-monthly, and monthly pay in Illinois

Illinois tax does not care how often you get paid. Because IL-700-T applies a flat rate to wages minus a fixed allowance, splitting the annual calculation across 52, 26, 24, or 12 periods produces the same yearly total — only the size and number of checks change. The real difference between frequencies is the allowance timing: a weekly worker gets a smaller allowance deduction each period but claims it 52 times. The annual figures below all come from one salary at one income.

Semi-monthly (24 checks, same dates each month) and bi-weekly (26 checks) are genuinely different: bi-weekly produces two extra paychecks a year, not two bigger ones.

Illinois hourly paycheck calculator

Switch "How are you paid?" to Hourly and enter your rate and typical weekly hours. The calculator annualises with the standard payroll convention — hourly rate × hours per week × 52 weeks — then runs the identical federal, FICA, and Illinois layers used for salaried workers. At $25 an hour for 40 hours, that is $52,000 of gross pay, $2,284 of Illinois tax, $4,060 of federal tax, and about $801 of take-home per weekly check.

Two hourly caveats worth stating. Hourly workers who actually log more than 40 hours in a typical week will earn more than the rate × 40 × 52 figure, so enter your real average hours and put the overtime premium portion in the Advanced options field. And part-year or seasonal work means annualised gross overstates what you earn — for those situations, divide your expected annual earnings out yourself rather than trusting the 52-week convention.

Illinois salary paycheck calculator

For a salaried worker, the annual figure is given and the question is what each check is worth. Illinois converts salary to a payroll period by simple division — a $120,000 salary paid monthly is $10,000 of gross — and the same division applies to the tax layers, except Social Security, which stops once year-to-date wages pass $184,500. That means a $120,000 monthly-paid employee sees a slightly larger net check in December than in January, even though gross is identical.

Salaried workers negotiating an offer should also check whether Illinois income tax is worth relocating for. The flat 4.95% rate is lower than most high-tax neighboring states, and because there are no state brackets, a raise is never partly wasted on a marginal-rate jump — though the exemption-allowance cliff described above behaves very much like one.

Illinois take-home pay examples

Every number below was produced by the same engine running in the calculator above — none of it is estimated by hand. Adjust the inputs and your own results replace these instantly.

Overtime and tips: Illinois does not conform to OBBBA

Moving to or from Illinois?

Take-home comparisons use the same withholding engines as the paycheck calculators — federal, FICA, and state lines side by side.

• Illinois → Indiana→

  Illinois 4.95% flat withholding versus Indiana 2.95% plus county tax — same federal and FICA line.

• Texas → Illinois→

  Texas 0% personal income tax versus Illinois 4.95% flat rate — compare take-home pay, Cook County vs Texas property taxes, and moving costs.

• Florida → Illinois→

  Florida 0% personal income tax versus Illinois 4.95% flat rate — compare take-home pay, housing affordability, and hurricane insurance differences.

• Illinois → Texas→

  Illinois 4.95% flat rate versus Texas 0% personal income tax — compare take-home pay, housing affordability, and property tax dynamics.

• Illinois → Florida→

  Illinois 4.95% flat rate versus Florida 0% personal income tax — compare take-home pay, homeowners insurance reality, and cost of living.

• California → Illinois→

  California progressive brackets up to 13.3% and 1.3% SDI versus Illinois flat 4.95% rate, accessible housing, and Chicago transit.

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PayAtlasUSA is an independent salary research site. It is not affiliated with ADP, Gusto, SmartAsset, or any payroll provider, and no third-party payroll service is connected to this calculator.