2026 Tax Tables
Illinois imposes a flat 4.95% income tax on wages and salaries, a rate that has been in effect since 2017 under the Illinois Income Tax Act. Employers use the IL-W-4 form to collect the employee's withholding allowances. Each allowance reduces the employee's annualized wages by $2,425 before applying the 4.95% rate, effectively reducing withholding for employees who claim them.
Calculate IllinoisWithholding →State Tax Rate
4.95% flat
State W-4 Form
IL-W-4
Tax Year
2026
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Illinois uses a flat 4.95% income tax rate on all wages. This rate has been unchanged since 2017 when it was increased from 3.75%.
Each allowance claimed on the Illinois IL-W-4 form reduces the employee's annualized income by $2,425. An employee claiming 3 allowances would reduce their taxable annual income by $7,275 before applying the 4.95% rate.
No. Illinois has its own IL-W-4 form. The federal W-4 and IL-W-4 are separate — employees should complete both.
Illinois does not have a standard deduction in the traditional sense. Instead, employees claim personal exemption allowances on the IL-W-4. Each allowance ($2,425) functions like a personal exemption deduction from income.