Illinois Bonus Tax Calculator
Data compiled and maintained by Edmond Daher · Updated 2026-08-02
Illinois bonus tax calculator
That big bite out of a Illinois bonus is withholding at work — a prepayment, not a special bonus tax. Illinois has no separate bonus rate, so it withholds using the aggregate method (about 4.95%) on top of the 22% federal prepayment and FICA. Put in your figures above to compare what's withheld now with your real tax at filing — and the refund or shortfall. Everything runs in your browser.
Quick answer: a separately paid bonus in Illinois is withheld at a flat 22% for federal income tax plus no separate Illinois rate — it's withheld as ordinary wages (about 4.95%), plus 7.65% FICA. None of that is the final number — a bonus is taxed at your marginal rate once you file, so the calculator above estimates what comes back or is still due.
Estimate only, not tax advice — terms.
Is Illinois's the aggregate method (~4.95%) bonus rate a "bonus tax"? No
Bonuses aren't taxed differently — only withheld differently. The real tax is your ordinary marginal rate, settled on your return, not the flat 22% on the check. If your real rate sits under 22%, the surplus refunds; if it runs above, you cover the shortfall. In this page's $14,000 example, about $550 of what's withheld is really over-payment you'd get back. Only FICA (7.65%) is a true tax that never returns.
The three cuts on a Illinois bonus: federal, state, and FICA
Federal withholding on a bonus. The IRS default holds back a flat 22% for federal income tax when the bonus is separate from your regular pay (IRS Pub 15). A mandatory 37% hits supplemental pay beyond $1,000,000 a year; neither figure is a special "bonus" rate, both are withholding defaults.
Illinois: the aggregate method. Illinois publishes no separate bonus rate, so a bonus is withheld as if it were ordinary wages. Because Illinois taxes income at a flat 4.95%, a separately paid bonus is effectively withheld near 4.95%.
The 7.65% is real. FICA — Social Security up to the wage base, plus 1.45% Medicare (and 0.9% more above $200,000) — is owed at exactly the rate it's withheld. That's why the calculator shows the same FICA under "withheld now" and "what it really costs" — there's nothing to refund; only the income-tax portion trues up.
Working out a whole paycheck? See the Illinois paycheck calculator.
What a $14,000 bonus really costs on a $61,000 Illinois income
Here's how a $14,000 bonus plays out for a single filer making $61,000 in Illinois:
- On the check: the employer holds back $3,080 for federal, $693 Illinois, and $1,071 for FICA — $4,844 in all (34.6% of the bonus), leaving about $9,156.
- The real bill: at filing the bonus is taxed roughly $3,223 in income tax (federal $2,530 + Illinois $693), with the identical $1,071 FICA on top.
- The gap: the flat 22% over-shoots your real rate by about $550, so that much is a refund later. Either way, the $1,071 FICA is final and won't come back.
Illustrative single-filer figures from this page's engine; your result depends on your total income and filing status.
How Illinois withholding scales from a $5,000 to a $100,000 bonus
Three bonuses — $5,000, $25,000, $100,000 — and what Illinois withholds from each on a $70,000 salary:
| Bonus | Federal | Illinois | FICA | Total | % of bonus |
|---|---|---|---|---|---|
| $5,000 | $1,100 | $248 | $383 | $1,730 | 34.6% |
| $25,000 | $5,500 | $1,238 | $1,913 | $8,650 | 34.6% |
| $100,000 | $22,000 | $4,950 | $7,650 | $34,600 | 34.6% |
Watch the percentage fall once Social Security maxes out; the income-tax slice trues up when you file regardless.
Bonus withholding in Illinois next to Indiana, Wisconsin and Missouri
A single filer earning $70,000 who gets a $10,000 bonus, in Illinois and neighboring Indiana, Wisconsin and Missouri:
| State | Bonus method | State withheld | Total withheld |
|---|---|---|---|
| Illinois | aggregate (~4.95%) | $495 | $3,460 |
| Indiana | aggregate (~2.95%) | $295 | $3,260 |
| Wisconsin | graduated 3.54–7.65% | $530 | $3,495 |
| Missouri | flat 4.7% | $470 | $3,435 |
Figures are the 22% federal plus state plus FICA for a single filer; the income tax you owe reconciles on your return.
Illinois bonus tax FAQ
How much is withheld from a bonus in Illinois for 2026?
On a separately paid bonus, Illinois takes about 4.95% (aggregate method), the federal side takes a flat 22% (37% beyond $1,000,000/yr), and FICA takes 7.65%. Those are withholding rates that settle up when you file — not a final tax.
Is a Illinois bonus taxed differently from my salary?
Not in the end. It may be withheld differently (a flat rate up front), but at filing a bonus is taxed exactly like the rest of your income, at your marginal rate.
Does my Illinois bonus ever come back at tax time?
The income-tax part can. If the flat 22% over-withheld relative to your real marginal rate, the excess is refunded; if you're a high earner above 22%, you pay more. FICA is never refunded.
Does Illinois have a separate bonus withholding rate?
No. Illinois has no separate supplemental rate, so a bonus is withheld with the aggregate method — as if it were part of your regular wages, effectively near 4.95%.
Bonus tax calculators near Illinois
Illinois paycheck calculator · all state bonus tax calculators →
Sources
- IRS Publication 15 (2026) — Supplemental Wages (flat 22% / 37% above $1M)
- Illinois income-tax status & rate: see the Illinois paycheck calculator sources (state DOR, verified 2026-08-02).