Illinois Estimated Tax Payments Calculator

2026 rules

Enter your expected income to see what to send Illinois and the IRS each quarter.

Your numbers

Filing status

Self-employment or business profit

W-2 wages

Other income (interest, dividends, gains, rental)

Illinois tax withheld from paychecks

Last year's Illinois tax (total on your return)

Leave at 0 to use this year's estimate only.

Federal tax withheld

Last year's federal tax (Form 1040 line 24)

Result

Illinois quarterly payment$851

Projected federal tax (incl. SE tax)$17,147
Projected Illinois tax$3,783
Illinois amount to pay in estimates$3,405
Illinois payment 1 · Apr 15, 2026$851
Illinois payment 2 · Jun 15, 2026$851
Illinois payment 3 · Sep 15, 2026$851
Illinois payment 4 · Jan 15, 2027$851
Federal amount to pay in estimates$15,433
Federal payment · Apr 15, 2026$3,858
Federal payment · Jun 15, 2026$3,858
Federal payment · Sep 15, 2026$3,858
Federal payment · Jan 15, 2027$3,858
First payment, state and federal$4,709

Illinois at a glance

Due dates: Apr 15, 2026, Jun 15, 2026, Sep 15, 2026, Jan 15, 2027
Rates: Illinois has a flat 4.95% income tax.

Illinois tax brackets for 2026

All filers (taxable income)
Rate	Taxable income
4.95%	over $0

Questions

When are Illinois estimated tax payments due for 2026?

Apr 15, 2026, Jun 15, 2026, Sep 15, 2026, Jan 15, 2027.

How much do I need to pay to avoid a penalty?

This calculator uses the federal safe harbor: 90% of this year's tax, or 100% of last year's (110% if your AGI is over $150,000), less withholding. A few states use a different share of the current year's tax, so check the Illinois estimated-tax instructions too.