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How Bonuses Are Taxed in Illinois (2026)
A bonus paid on a separate check in Illinois has a flat 22% federal tax withheld (37% on cumulative supplemental wages over $1,000,000 in a year), 7.65% FICA, and Illinois's flat 4.95% state income tax. Withholding is not a higher tax rate — it is just how much your employer holds back up front; your actual tax on the bonus is settled when you file, and any over-withholding comes back as refund.
| Component | Rate on the bonus |
|---|---|
| Federal income tax (supplemental, percentage method) | 22% flat · 37% above $1,000,000/yr |
| Social Security | 6.2% (up to $184,500 of total wages) |
| Medicare | 1.45% · +0.9% above $200,000 |
| Illinois state tax | 4.95% flat |
Some employers instead use the aggregate method — adding the bonus to your regular paycheck and withholding as if that were every check — which can withhold more or less than the flat 22%. The calculator above uses the flat-rate (percentage) method.
Illinois Bonus Take-Home by Amount (2026)
Flat-rate (percentage) method, single filer, bonus paid separately on top of a $65,000 salary. Enter your own numbers in the calculator above — this table is a starting point.
| Bonus | Federal (22%) | FICA | Illinois tax | Take-home |
|---|---|---|---|---|
| $1,000 | $220 | $77 | $50 | $654 |
| $2,500 | $550 | $191 | $124 | $1,635 |
| $5,000 | $1,100 | $383 | $248 | $3,270 |
| $10,000 | $2,200 | $765 | $495 | $6,540 |
| $15,000 | $3,300 | $1,148 | $743 | $9,810 |
| $25,000 | $5,500 | $1,913 | $1,238 | $16,350 |
How Illinois Paycheck Tax Is Calculated (2026)
Source: Illinois Department of Revenue| Flat state rate | 4.95% |
|---|---|
| Personal exemption | $2,425 |
Federal Tax & FICA (shared across all states)
| Filing status | Standard deduction |
|---|---|
| Single | $16,100 |
| Married Filing Jointly | $32,200 |
| Head of Household | $24,150 |
| Federal brackets (all filing statuses) | 10% / 12% / 22% / 24% / 32% / 35% / 37% |
|---|---|
| Social Security | 6.2% up to $184,500 wage base |
| Medicare | 1.45% on all wages, +0.9% above $200,000 single/HoH, $250,000 MFJ |
Guideline version 2026-IL-v1 · Last verified 2026-07-26
Illinois Bonus Tax FAQ
How much are bonuses taxed in IL?
An Illinois bonus paid separately has the flat 22% federal supplemental tax withheld (37% above $1,000,000/year), 7.65% FICA, and Illinois's flat 4.95% state income tax. Illinois applies its flat rate to supplemental wages, so combined withholding is roughly 34.6%.
What is the Illinois bonus tax rate for 2026?
22% federal + 4.95% Illinois + 6.2% Social Security + 1.45% Medicare. A $5,000 Illinois bonus has about $1,100 federal, $248 Illinois, and $383 FICA withheld.
Is an Illinois bonus taxed at a higher rate than salary?
No. Illinois's 4.95% is a true flat tax applied identically to a bonus and to regular wages. Only the federal withholding method differs for a separate bonus.
Methodology & Source
Illinois state tax figures sourced from Illinois Department of Revenue (https://tax.illinois.gov/), citing 35 ILCS 5/201 — flat 4.95% rate (Illinois Constitution art. IX, § 3 prohibits graduated rates). Federal brackets, standard deductions (single/MFJ/HoH), and FICA constants sourced from the IRS (Revenue Procedure 2025-32; married-filing-jointly Additional Medicare threshold of $250,000 is a separate, unindexed statutory figure). Illinois's married-filing-jointly and head-of-household figures have been independently verified against the source above.
Bonus federal withholding uses the flat supplemental-wage rate (22%, 37% above $1,000,000 cumulative supplemental wages/year), per IRS Publication 15 (Circular E), Employer's Tax Guide, 2026 edition — the alternative "aggregate method" is not modeled. Illinois publishes no separate supplemental withholding rate, so the calculator estimates the state tax on the bonus from your marginal bracket.
This is an estimate based on standard single-filer federal, FICA, and IL state calculations. Actual withholding may differ based on your W-4 elections, pre-tax deductions (401k, health insurance), and other factors.
Guideline version: 2026-IL-v1 · Effective: 2017-07-01 · Last verified: 2026-07-26