Estimate Illinois state income tax withheld from a paycheck using W-4 allowances.
This estimates Illinois state income-tax withholding from gross wages, W-4 filing status and allowances, using an approximate state rate. It is a reference estimate, not the state payroll table. State withholding estimated using an approximate state rate. Verify with the official Illinois payroll / tax source.
Withholding
Withholding ≈ (gross wages − filing allowance) × approximate state rate
Approximate reference estimate only — actual withholding follows the official state withholding tables.
No. Actual withholding uses the state's official percentage method or wage-bracket tables and can differ from this estimate.
Use your combined annual wages to get a closer estimate, then split withholding across employers.