Illinois Paycheck Calculator
Free take-home pay estimator for Illinois employees · 2026 tax rates · Updated January 2026
How Illinois paycheck taxes work
Illinois has a flat 4.95% income tax — simple to calculate, with no brackets to worry about.
- Illinois's constitution requires a flat income tax rate — all income is taxed at the same 4.95%.
- There is no state standard deduction, but a $2,425 personal exemption reduces taxable income.
- Illinois does not tax retirement income including Social Security, pensions, or 401(k) distributions.
Federal income tax withholding (2026)
Federal income tax withholding is calculated using the annualization method from IRS Publication 15-T. Your per-period gross pay is annualized, reduced by the standard deduction ($15,000 single / $30,000 married / $22,500 head of household in 2026), and then taxed at the applicable bracket rates. The resulting annual tax is divided by your number of pay periods.
2026 federal tax brackets
| Taxable Income (Single) | Rate |
|---|---|
| $0 – $11,925 | 10% |
| $11,926 – $48,475 | 12% |
| $48,476 – $103,350 | 22% |
| $103,351 – $197,300 | 24% |
| $197,301 – $250,525 | 32% |
| $250,526 – $626,350 | 35% |
| Over $626,350 | 37% |
FICA: Social Security & Medicare
FICA taxes are the same in every state. Social Security is withheld at 6.2% on wages up to $176,100 (2026 wage base). Once your wages reach that cap in a calendar year, Social Security withholding stops. Medicare is withheld at 1.45% with no wage cap. An additional 0.9% applies to wages above $200,000 (single) or $250,000 (married).
Illinois state income tax details
Illinois taxes all earned income at a flat 4.95% rate. This applies equally to all wage earners regardless of income level, making the calculation straightforward: multiply your taxable wages by 4.95%.
Pre-tax deductions and your paycheck
Traditional 401(k) contributions and employer-sponsored health insurance premiums (Section 125/cafeteria plan) reduce your federal and state taxable income, lowering your income tax withholding. However, 401(k) contributions do not reduce FICA (Social Security and Medicare) wages. Health insurance premiums under a Section 125 plan do reduce FICA wages. Use the "Show deductions" section above to model your specific situation.
Frequently asked questions
- Illinois has a flat state income tax rate of 4.95%. This rate applies to all taxable income equally, regardless of how much you earn. Use the calculator above to see your exact per-paycheck withholding.
- Chicago levies a city tax (Personal Property Replacement Tax via employers). Net impact on employees is indirect. Use the calculator above for state income tax — contact your employer or local tax authority for local tax withholding specifics.
- Start with your gross pay per paycheck. Subtract: (1) federal income tax based on your filing status and 2026 brackets; (2) Social Security at 6.2% up to the $176,100 wage base; (3) Medicare at 1.45%; (4) Illinois state income tax. Any pre-tax deductions like 401(k) or health insurance reduce your taxable income further. The calculator above does this math instantly.
- Illinois's 4.95% flat income tax applies to wages and salaries. Whether Illinois taxes Social Security retirement benefits depends on your specific situation — check the Illinois Department of Revenue for current exemption rules. Paycheck withholding (what this calculator estimates) applies only to wages, not retirement benefits.
- Illinois does not require additional state payroll contributions beyond state income tax withholding. Some states (notably California, New Jersey, and New York) require workers to contribute to state disability insurance (SDI) or paid family leave (PFL) programs — Illinois is not one of them.
Last updated: January 2026 · Data source: IRS Publication 15-T (2026), Illinois Department of Revenue · This tool is for estimation only.
Related guides
- How does paycheck withholding work? — Step-by-step explanation of federal withholding, FICA, and state tax calculation.
- W-4 withholding guide — How to fill out the redesigned W-4 and avoid under- or over-withholding.