Illinois Income Tax 2026

Illinois has a flat 4.95% income tax for 2026. The standard deduction is $0 (single) / $0 (married filing jointly). Flat 4.95% income tax on net income for tax year 2026 (confirmed by IL-700-T 2026 withholding booklet and DOR Informational Bulletin FY 2026-15). Graduated rates are prohibited by the Illinois Constitution (the 2020 'Fair Tax' graduated-rate amendment was rejected by voters). No standard deduction - Illinois has none. Instead it uses a personal exemption allowance: $2,925 per person for tax year 2026 (up from $2,850 in 2025), so an effective $5,850 for a married couple filing jointly, plus $2,925 per dependent; additional $1,000 exemption if taxpayer/spouse is 65+ and/or legally blind. The exemption is fully disallowed (=$0) if federal AGI exceeds $250,000 (single/all other filing statuses) or $500,000 (married filing jointly). Illinois starts from federal AGI, then largely exempts retirement income: Social Security benefits, qualified pension/annuity income, IRA and 401(k) distributions are subtracted out (Schedule M / Form IL-1040), making IL one of the most retirement-friendly tax states. No local/city income taxes anywhere in Illinois (no municipal wage tax). Other credits: property-tax credit (5% of IL property tax paid on principal residence), K-12 education expense credit, and earned income credit (20% of federal EITC).