Illinois uses a 4.95% withholding rate after applicable Illinois withholding exemptions. The calculator exposes both IL-W-4 allowance fields independently from the federal W-4.
What this calculator includes
The estimate combines the 2026 federal percentage method, Social Security, Medicare, supported state withholding, common pre-tax deductions and optional extra withholding. It shows annual, monthly, biweekly and weekly take-home equivalents.
How to get a closer estimate
- Match the pay frequency on your actual pay stub.
- Copy the filing status and W-4 entries you gave your employer.
- Add traditional 401(k) and common pre-tax health deductions when applicable.
- Use the state panel for state-certificate details instead of assuming the federal W-4 controls state withholding.
Why your actual paycheck may differ
Bonuses, supplemental wages, year-to-date wage caps, local taxes, special benefits, reciprocity and employer-specific payroll timing can change real withholding. PaycheckRadar is an estimator, not a payroll processor.
Official sources
Tax year 2026. Last reviewed September 27, 2026.