The formulas
- Taxable income = income - standard deduction - personal exemptions (when applied), not below zero
- Tax = 4.95% x Illinois base income less exemptions
- Exemption allowance $2,925 per person for 2026; none when federal AGI exceeds $250,000 ($500,000 joint)
- Illinois income tax = tax from the rate schedule
How it works
Tax year: 2026.
Illinois taxes income at a flat 4.95%. Enter income before state deductions and choose whether to apply the state standard deduction and personal exemptions, or enter taxable income and switch them off. The tool computes state income tax only; credits other than those named are not applied.
Illinois taxes net income at a flat 4.95 percent. There is no standard deduction. The 2026 exemption allowance is $2,925 for each filer and dependent, plus $1,000 for age 65 or blindness, and it is not allowed when federal AGI is over $250,000 ($500,000 joint). The tool applies the filer exemptions; add dependents yourself.
Local taxes: Illinois cities and counties do not levy a local income tax on wages.
Illustrative figures only. Check the result against your firm's methodology before relying on it.
Common questions
What is the Illinois income tax rate for 2026?
Illinois taxes income at a flat 4.95% for 2026. Tax = 4.95% x Illinois base income less exemptions.
Does Illinois have a standard deduction?
No. Illinois has no standard deduction of its own.
Are there local income taxes in Illinois?
Illinois cities and counties do not levy a local income tax on wages.
Sources
- Illinois DOR, 2026 IL-700-T withholding tables (4.95% effective January 1, 2026)
- Illinois DOR, What is the Illinois personal exemption allowance?
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