How Much Tax Is Taken Out of a Paycheck in Illinois?
Three taxes come out of every Illinois paycheck — federal income tax withholding, the 4.95% state flat tax and FICA — and together they typically account for about 17% to 30% of gross pay. Here is how each one is calculated, and what it works out to at every income level.
The short answer
For a single filer with no dependents and no benefit deductions, the total tax bite in Illinois looks like this:
| Annual salary | Total tax | Take-home | Effective rate |
|---|---|---|---|
| $30,000 | $5,200 | $24,800 | 17.3% |
| $40,000 | $7,660 | $32,340 | 19.2% |
| $50,000 | $10,120 | $39,880 | 20.2% |
| $60,000 | $12,580 | $47,420 | 21.0% |
| $75,000 | $17,120 | $57,880 | 22.8% |
| $100,000 | $25,770 | $74,230 | 25.8% |
| $150,000 | $43,634 | $106,366 | 29.1% |
Enter your own figures to see the exact split, including dependent credits and pre-tax deductions:
What comes out of your Illinois paycheck
- Gross pay $0 / yr$0.00
- Pre-tax deductions$0.00
- Federal income tax$0.00
- Illinois income tax flat 4.95%$0.00
- Social Security wage base reached$0.00
- Medicare$0.00
- Additional Medicare 0.9%$0.00
- After-tax deductions$0.00
- Total taxes$0.00
- Federal income tax$0
- Illinois income tax$0
- FICA (Social Security + Medicare)$0
- All taxes$0
- Take-home pay$0
The three taxes, one at a time
1. Federal income tax withholding — the variable one
This is the largest deduction for most people and the only one that depends on your personal circumstances. Your employer takes your pay for the period, annualizes it, finds where that figure lands in the IRS Publication 15-T rate schedule for your filing status, subtracts the dependent credits from Step 3 of your Form W-4, and divides back down to the pay period.
Because the schedule is progressive, the percentage rises with income. On $50,000 a single filer's federal withholding is about 7.6% of gross; on $150,000 it is about 16.5%. What people usually misread is the difference between the bracket and the rate actually paid — a $75,000 earner sits in the 22% bracket but pays about 10.2% of gross in federal withholding, because only the top slice of income is taxed at 22%.
2. Illinois income tax — the predictable one
Illinois takes 4.95% of wages after subtracting the allowances claimed on Form IL-W-4. That is the entire calculation. No brackets, no filing-status difference, no city tax, no county tax. Each basic allowance shelters $2,925 of wages in 2026, worth $144.79 of tax across the year. The Illinois income tax rate guide covers the state side in depth.
3. FICA — the flat one
Social Security takes 6.2% of wages until year-to-date pay reaches $184,500 in 2026, after which it stops for the rest of the year. Medicare takes 1.45% on everything with no ceiling. Together that is 7.65%, matched by your employer. A single filer earning over $200,000 also pays an Additional Medicare Tax of 0.9% on the excess, which the employer does not match.
A traditional 401(k) contribution reduces the wages subject to federal and Illinois income tax but not the wages subject to FICA. Health, dental and vision premiums, FSA contributions and payroll HSA contributions reduce all three — which makes them the most tax-efficient dollar in a benefits package.
The anatomy of one paycheck
A bi-weekly paycheck on a $65,000 salary, single filer, with a $150 health premium and 5% going into a traditional 401(k):
| Line | Amount | Effect |
|---|---|---|
| Gross pay | $2,500.00 | $65,000 ÷ 26 |
| Health premium (Section 125) | −$150.00 | Cuts federal, Illinois and FICA |
| 401(k) at 5% | −$125.00 | Cuts federal and Illinois, not FICA |
| Wages subject to income tax | $2,225.00 | |
| Wages subject to FICA | $2,350.00 | |
| Federal income tax | −$183.15 | |
| Illinois income tax 4.95% | −$110.14 | |
| Social Security 6.2% | −$145.70 | |
| Medicare 1.45% | −$34.08 | |
| Net pay | $1,751.93 |
Note what the $275 of pre-tax deductions actually cost: gross drops by $275 but net drops by only about $217, because the deductions save roughly $58 in tax. That is the practical case for using pre-tax benefits rather than paying for the same things after tax.
What comes out of an hourly paycheck
| Hourly rate | Gross weekly | Federal | Illinois | FICA | Net weekly |
|---|---|---|---|---|---|
| $15.00 | $600.00 | $30.08 | $29.70 | $45.90 | $494.32 |
| $18.00 | $720.00 | $44.48 | $35.64 | $55.08 | $584.80 |
| $20.00 | $800.00 | $54.08 | $39.60 | $61.20 | $645.12 |
| $25.00 | $1,000.00 | $78.08 | $49.50 | $76.50 | $795.92 |
| $30.00 | $1,200.00 | $102.08 | $59.40 | $91.80 | $946.72 |
| $35.00 | $1,400.00 | $138.19 | $69.30 | $107.10 | $1,085.41 |
The hourly paycheck calculator handles overtime, double time and a second pay rate if your timesheet is more complicated than a flat 40.
Deductions that are not taxes
Plenty of what disappears between gross and net is not tax at all. Illinois law is strict about which of these an employer may take: under Section 9 of the Wage Payment and Collection Act, a deduction is lawful only when required by law, for the employee's benefit, expressly authorized in writing at the time it is made, or made under a valid court order.
- Health, dental and vision premiums — pre-tax through a Section 125 cafeteria plan
- Retirement contributions — traditional 401(k) pre-tax, Roth 401(k) after tax
- HSA and FSA contributions — pre-tax, and exempt from FICA as well
- Life and disability insurance — treatment varies by policy type
- Union dues — after tax
- Wage garnishment — after tax, limited by the Illinois 15% rule
- Illinois Secure Choice — a Roth IRA at a default 5% of pay, if your employer has five or more employees and offers no plan of its own. You can opt out.
If the number looks wrong
Start with the two forms. Ask HR for a copy of the Form W-4 and Form IL-W-4 currently on file — people are often surprised by what they submitted years ago. Check the filing status, the Step 2 multiple-jobs box and the Step 3 dependent amount, since those three fields drive most of the federal figure.
Then check the year-to-date column rather than a single paycheck. A one-off overtime week or a bonus distorts a single stub but not the annual picture. If year-to-date withholding is genuinely off track, submit a new W-4 — you can do it at any time and as often as you like, and payroll must apply it no later than the start of the first pay period ending on or after the 30th day after you hand it in. The withholding guide walks through both forms field by field.
People also ask
Between about 17% and 30% for most workers, rising with income. A single filer on $40,000 loses roughly 19% to federal withholding, Illinois tax and FICA combined; at $75,000 it is about 23%; at $150,000 about 29%. The Illinois share is always exactly 4.95% and FICA is always 7.65% up to the wage base — it is the federal portion that climbs, because only federal tax is progressive.
On a $1,000 weekly paycheck for a single filer with no dependents, roughly $204 comes out: about $78 federal withholding, $49.50 Illinois income tax, $62 Social Security and $14.50 Medicare — leaving about $796. Add a health premium or a 401(k) contribution and the tax figure drops, because both reduce the wages that tax is calculated on.
Usually one of three things. Payroll may be annualizing a partial pay period as though it were a full one. Your Form W-4 may be missing dependent credits you are entitled to claim in Step 3. Or a first paycheck may carry benefit deductions and a signing bonus at the flat 22% supplemental rate on top of normal withholding. Compare the stub against the calculator on this page — if the gap is large, the W-4 is the first place to look.
Federal, comfortably, for almost everyone. Illinois takes a flat 4.95%, while federal withholding on a $75,000 salary runs around 10.2% of gross and rises from there. FICA at 7.65% also exceeds the Illinois share for anyone below the Social Security wage base. On a typical middle-income Illinois paycheck the split is roughly half federal income tax, a third FICA and a fifth state tax.
Exactly the same as anywhere else in Illinois. Chicago levies no city income tax and neither does Cook County, so a Chicago paycheck and a Champaign paycheck at the same salary and the same W-4 produce identical withholding. What is higher in Chicago is the sales tax at 10.25% and the local minimum wage at $17.05 — neither of which affects your pay stub deductions.
FICA is the Federal Insurance Contributions Act, and it funds Social Security and Medicare. It appears on a pay stub as two lines: OASDI at 6.2% of wages up to the $184,500 annual wage base for 2026, and Medicare at 1.45% on all wages with no cap. Your employer pays a matching 7.65%. Above $200,000 for a single filer an Additional Medicare Tax of 0.9% applies to the employee only.
Only in narrow circumstances, and FICA never stops. You may claim exempt from federal withholding on Form W-4 if you had no federal tax liability last year and expect none this year — but claiming exempt when you do owe leads to penalties, and the election expires every February. Illinois withholding can be reduced through allowances on Form IL-W-4 but not eliminated for taxable wages. What you can legitimately do is lower taxable wages through pre-tax contributions to a 401(k), HSA or Section 125 plan.
Run your gross pay, filing status and deductions through the calculator on this page and compare the result to your pay stub. A difference of a few dollars is normal rounding. A difference of tens of dollars usually means the W-4 on file does not match what you think it says — ask HR for a copy. The IRS Tax Withholding Estimator is a useful second check for the federal side, and the year-to-date column on your December stub is the most reliable way to confirm you are on track.
Sources
- IRS Publication 15-T — Federal Income Tax Withholding Methods
- IDOR — Booklet IL-700-T
- SSA — 2026 Social Security wage base
- Illinois Department of Labor — Wage Payment and Collection Act
Estimates for planning only. Actual withholding depends on the forms your employer holds and on payroll rounding conventions. Not tax advice.