For more on how deductions change taxable wages, see our
pre-tax vs. post-tax deductions guide.
Illinois Paycheck Tax Calculator: How Illinois Withholding Works
An Illinois paycheck calculator has one state tax
to get right: 4.95% of wages after your IL-W-4 allowances. On your
pay stub it usually appears as
SIT or IL state withholding;
our pay stub abbreviations list
explains the other codes.
Federal Withholding for Illinois Paychecks
Federal withholding uses your Form W-4 and the 2026 IRS Publication
15-T tables. The calculator supports filing status, Step 2(c), Step 3
credits and Step 4(a), 4(b) and 4(c). If you claim the new overtime
or tips deductions, our
W-4 Step 4(b) worksheet guide
shows how to enter them, and our
2026 federal tax withholding guide
covers the rest.
Reciprocity: Wisconsin, Iowa, Kentucky and Michigan
Illinois has reciprocal agreements with
Wisconsin,
Iowa,
Kentucky and
Michigan.
Residents of those states who work in Illinois file Form IL-W-5-NR
with their employer and have only their home state's tax withheld.
Commuters from Indiana
and Missouri
don't have that option; they pay Illinois tax on Illinois wages and
claim a credit at home.
No Local Income Tax
No Illinois city or county taxes wages. Chicago, Aurora, Naperville,
Rockford and every other city add nothing to paycheck deductions.
The Chicago and Cook County rules that do affect pay are the higher
minimum wages above and local paid leave ordinances.
Illinois Secure Choice
Employers with five or more employees that don't offer a
retirement plan must enroll workers in
Illinois Secure Choice, a state-run Roth IRA. The default
contribution is 5% of gross pay, taken after taxes, so it lowers
take-home pay without lowering Illinois or federal tax. You can
change the rate or opt out. Enter it as an other post-tax deduction
in the calculator.
Bonuses
Bonuses are subject to Illinois withholding at the same 4.95% rate,
plus federal withholding (usually a flat 22% on separately paid
bonuses) and FICA. See why bonuses are taxed so high.
Employer Payroll Costs in Illinois
Employers pay state unemployment tax
on the first $14,250 of each employee's wages in 2026. Most new
employers pay 3.35%, and experienced rates run from 0.75% to 7.05%.
Employers also pay their share of Social Security and Medicare and
federal unemployment tax. None of it comes out of your pay. At
year-end, our W-2 form generator
can use the same wage and withholding totals.
Why Your Actual Illinois Paycheck May Differ
This calculator is a close estimate, not your employer's payroll
run. Your IL-W-4 on file, benefit elections, a Secure Choice or
other after-tax deduction, year-to-date wages and a 27th biweekly
payday in some years can all move the result a little.
Three-paycheck months
change monthly cash flow but not the tax on each check. For a full
checklist, see why your paycheck is lower than expected.
Official 2026 Illinois Payroll Sources
Payroll facts on this page are checked against the
2026 IL-700-T withholding tables,
the Illinois exemption allowance rules,
the 2026 IDES contribution rate notice,
the Cook County and Chicago minimum wage announcement,
Illinois Secure Choice
and IRS Publication 15-T for 2026.
Reviewed September 24, 2026.