United States
Illinois: what the state takes
Illinois charges its own income tax on top of federal tax. Here is the rate, the return, the date and where the official rules live.
Agency page last read 11 September 2026.
State rate
4.95%
Flat 4.95% after the personal exemption
Resident return
Form IL-1040
Illinois Department of Revenue
Due
15 April, following the federal deadline
Weekends and holidays can push it on
Try a figure
Yearly income
How you file
Illinois tax
$3,571
Top state rate you touch
4.95%
- Kept before federal tax$57,577
- Federal income tax$13,852
- Illinois tax$3,571
Flat rate of 4.95% on $72,150 after a $2,850 deduction.
Filing in Illinois
- Who collects it
- Illinois Department of Revenue
- Return
- Form IL-1040
- Deadline
- Usually 15 April, following the federal deadline
Federal comes on top
Whatever your state does, the IRS wants Form 1040 by 15 April, plus Social Security and Medicare through your wages or self employment tax. State tax paid can sometimes be deducted federally if you itemise, within a yearly cap.