Illinois Paycheck Calculator 2026 — 4.95% Flat Tax & Take-Home Pay

Illinois taxes all income at a single flat rate of 4.95% — the state constitution forbids graduated brackets. See exactly what that costs on your paycheck, plus federal tax and FICA — free, private, no sign-up.

How Illinois Paychecks Work

1. Federal tax: progressive brackets 10%–37% minus the $16,100 standard deduction (single, 2026) — same as everywhere.
2. FICA: 6.2% Social Security (up to the $184,500 wage base) + 1.45% Medicare — same as everywhere.
3. State tax: 4.95% flat. Illinois applies one rate to Illinois base income (federal AGI with state adjustments, minus a $2,625 personal exemption for single filers in 2026). No brackets to climb — every taxable dollar costs the same.

Worked Example: $85,000 Single Filer

Illinois vs Texas vs California on $85,000

The same single filer keeps $64,549 in Illinois against $68,627 in Texas and $63,760 in California. Illinois' flat 4.95% sits between the two extremes: cheaper than California's progressive stack, costlier than zero-tax Illinois. Model any state in the calculator.

Illustrative estimate for a single filer, standard deduction, no pre-tax contributions. Confirm with the IRS or a tax professional.

Federal Withholding on a Illinois Paycheck

Only one income tax touches a Illinois paycheck: the federal one. Withholding follows the IRS percentage method in Publication 15-T, and three inputs drive it: your filing status, the dependents and credits you claim on Form W-4, and any extra withholding you request. Change any of the three and the same salary produces a different stub, which is why two Illinois workers earning $85,000 can take home different amounts.

Federal tax is progressive, which means it applies in slices, not to the whole salary at once. Only the dollars inside each bracket are taxed at that bracket's rate, so a single filer's effective rate is always lower than their top marginal rate. The standard deduction then removes a further slice of income from tax entirely before the brackets even start. Pre-tax items shrink the taxable wage base further: 401(k) contributions and health premiums taken pre-tax reduce the wages the percentages apply to, though the exact treatment differs by deduction type, so read your stub labels rather than assuming.

Our US paycheck calculator models this with an editable withholding percentage instead of hard-coding tables that Congress and inflation adjust every year. If you want the precise official arithmetic for the current year, Publication 15-T is the source the payroll industry itself uses.

FICA: the Two Lines That Always Appear

Below the federal line sit two flat deductions that behave nothing like income tax. Social Security takes 6.2% of wages up to the Social Security Administration's annual wage base, a cap it resets every year. Medicare takes 1.45% of all wages with no cap, plus an additional 0.9% on earnings above $200,000 for single filers ($250,000 joint) — those thresholds are set in statute, not adjusted annually. Your employer matches the 6.2% and the 1.45% dollar for dollar; the additional 0.9% is employee-only.

On the $85,000 example: Social Security is $85,000 x 0.062 = $5,270, comfortably below any recent wage-base cap, and Medicare is $85,000 x 0.0145 = $1,232.50. Together with federal withholding that is the entire deduction stack on a Illinois stub. There is no third line, which is exactly the point of the next section.

What Illinois Does Differently

Illinois' flat 4.95% rate is locked in by the state constitution — lawmakers cannot graduate it without an amendment, so the rate moves only by legislation (it has been 4.95% since July 2017). Withholding follows Form IL-W-4 and the Illinois Department of Revenue tables. Two quirks matter on the stub: Illinois starts from federal AGI then applies its own $2,625 personal exemption (single, 2026), and retirement income — including 401(k) distributions and pensions — is largely excluded from Illinois tax. There is no local income tax in most of Illinois, but property taxes rank among the nation's highest, which is where the state recoups revenue.

Overtime and Pay-Frequency Math

Illinois follows the federal Fair Labor Standards Act: non-exempt employees earn 1.5x their regular rate for hours over 40 in a week, with no stricter state daily-overtime rule on top. At $30/hour and a 45-hour week: 40 x $30 = $1,200 straight time, 5 x $45 = $225 overtime, $1,425 gross for the week. Salaried exempt employees are outside this rule under the duties-and-salary-basis test, so a $85,000 salary means $85,000 of gross regardless of hours.

Pay frequency then decides the per-check number without changing the annual total. On $85,000: weekly (52) = $1,634.62; biweekly (26) = $3,269.23; semi-monthly (24) = $3,541.67; monthly (12) = $7,083.33. The existing $85,000 example uses biweekly, the most common Illinois schedule. Note that overtime and bonuses can push individual checks into higher withholding on that check alone; withholding per check annualizes the amount, so a spike check withholds as though you earned at that pace all year, with the balance settling at filing time.

New to Illinois Paychecks: Reading Your First Stub

A first Illinois pay stub surprises newcomers in two ways: there is no state line at all, and the federal and FICA lines look larger than expected because nothing else shares the load. Read it top to bottom. Gross is what you earned. Pre-tax items come off next. FITW (federal income tax withheld) follows your W-4. Then the two FICA lines. The remainder is net. The year-to-date column repeats the same stack cumulatively, which is how you spot a drift early — if YTD federal withholding looks high relative to gross in March, file a new W-4 rather than waiting until filing season. Anyone arriving mid-year should set the W-4 for the new situation on day one: settings calibrated to a previous state system will systematically over- or under-withhold here. Our US paycheck calculator lets you model the stub before the first one prints.

Tipped, Hourly, and Third-Paycheck Months

Illinois hospitality runs on tipped wages, and the federal rules are specific. Employers may pay a cash wage as low as $2.13 per hour provided tips bring total hourly earnings to at least the $7.25 federal minimum; if they do not, the employer makes up the difference. Overtime for tipped and hourly staff alike is 1.5 times the regular rate past 40 hours a week. Separately, biweekly earners get two third-paycheck months every year: 26 paychecks cannot divide evenly into 12 months, so two months contain three paydays. The annual total is unchanged, but budgeting monthly on two checks and treating the third as surplus is the standard move. Monthly billers should note the mirror image: semi-monthly schedules never produce a third check, so compare offers on annual gross, not per-check size.

Self-Employed in Illinois: What Changes

Without an employer there is no withholding at all, so the full stack lands on you four times a year. Self-employment tax replaces both halves of FICA: 12.4% for Social Security up to the annual wage base plus 2.9% for Medicare, with the additional 0.9% over the statutory thresholds exactly as for employees — 15.3% combined before income tax. Half of that combined amount is deductible when computing income tax, which softens it but does not remove it. Federal estimated payments fall on the fixed calendar: January 15, April 15, June 15 and September 15, shifting to the next business day when the date lands on a weekend. Illinois adds nothing on top: no state estimates, no state return, no state-level equivalent to argue about. Miss a federal quarter and interest accrues from the due date, so new freelancers should set calendar reminders before the first April deadline surprises them. Keep 25 to 30 percent of each client payment in a separate account and the quarters stop hurting.

Bonuses, Commissions, and Supplemental Pay

Not everything on a Illinois stub follows the salary rules. Bonuses, commissions, severance, and back pay are supplemental wages, and employers may withhold federal tax on them at a flat 22% up to $1 million in a year (37% above that), instead of running them through the W-4 percentage method. That is why a $5,000 bonus can arrive as $3,900 before FICA even though your salary withholding implies a lower rate: $5,000 x 0.22 = $1,100 held back, plus 6.2% Social Security and 1.45% Medicare on top. Illinois adds nothing either way, so a Illinois bonus beats the same bonus in California by the state slice alone. The flat rate is only withholding, not the final tax — the actual liability settles at filing time against your real marginal rate, which is why bonus-heavy earners in Illinois often see meaningful refunds. Overtime already covered above counts as regular wages, not supplemental pay, so the two rules never stack on the same dollar.

The Honest Footnote: Total Burden Matters

The flat rate is only half the Illinois story. Property taxes in the Chicago area run 2%+ of home value — among the highest in the US — and the state's overall tax burden lands mid-pack nationally once everything is counted. Remote workers generally owe tax where they physically live. Anyone comparing an Illinois offer against Illinois or Florida should price property tax, not just the stub.

Frequently Asked Questions

Sources: Illinois Department of Revenue (tax.illinois.gov); 4.95% flat rate (35 ILCS 5/201); $2,625 personal exemption 2026. Federal figures: IRS Rev. Proc. 2025-32, SSA.gov. Accessed 2026-11-01.

Disclaimer: Estimates only — not tax advice. Confirm with the IRS or a tax professional.