How to pay Illinois estimated taxes.

Illinois collects its own estimated tax through the Illinois Department of Revenue, separate from the IRS. Here’s who needs to pay, when, and how to pay online.

Do you need to pay?

You must make estimated payments if you expect your 2026 Illinois tax to be more than $1,000 after subtracting Illinois withholding, pass-through withholding, and credits (including the pass-through entity tax credit and credit for tax paid to other states).

You generally avoid the penalty if you pay, in four equal timely installments, at least 90% of this year's tax or 100% of last year's tax. Illinois has no 110% rule for higher incomes.

If you underpay: Late payment penalty of 2% of the underpaid amount if an installment is 1 to 30 days late, or 10% if it is 31 or more days late, figured on Form IL-2210.

For how to pick a safe amount, see how much to pay in estimated taxes.

Deadlines

Four equal installments due April 15, 2026, June 15, 2026, September 15, 2026, and January 15, 2027. This matches the federal schedule. You can also pay the full year's estimate by April 15.

Payment	Due
1st	April 15
2nd	June 15
3rd	September 15
4th	January 15 of the next year

A date on a weekend or holiday moves to the next business day. Pay at least two business days early.

Paying Illinois, step by step

What you need

Nothing to set up. MyTax Illinois takes payments without an account.
Your Social Security number and a copy of last year's Illinois return.
Your bank routing and account numbers.

Start at MyTax Illinois, Illinois's official payment site.

Go to MyTax Illinois. You don't need an account, but you do need your IL-PIN (you can look it up with your SSN and driver's license or state ID).
In the Individuals panel, select Make an Individual Income Tax Payment.
Enter your identifying information and IL-PIN, then choose an estimated payment for tax year 2026.
Enter your bank account details and the payment amount.
Submit and save the confirmation code. Do not mail a voucher for an electronic payment.

Other ways to pay: Pay by credit card (MasterCard, Discover, American Express, Visa) through the link at tax.illinois.gov/payments/creditcard; the card processor charges a convenience fee. You can also mail a check with the IL-1040-ES voucher, or enroll in EFT with Form EFT-1.

Illinois will not fill these payments in for you. Your preparer has to enter each estimated payment on your Illinois return. Keep your own record of the date, amount, and confirmation number.

Extension payments

Illinois gives an automatic six-month extension to file (to October 15 for calendar year filers). You don't file a form to get it. It does not extend the time to pay. To pay tentative tax by April 15, use Form IL-505-I or choose an extension payment in MyTax Illinois.

Make this year's first estimated payment as a separate transaction, marked as an estimate for the current year.

Good to know

Online payments need your IL-PIN; if you don't have one assigned, you have to use another payment method.
Farmers (two-thirds of federal gross income from farming) and people 65 or older living permanently in a nursing home don't have to make estimates.
Illinois applies each payment to the earliest due date unless you tell it otherwise.
Pass-through entity tax paid by your partnership or S corporation counts as a credit when you figure whether you owe estimates.
Paying other states? See the payment links for every state's official site, and the federal walkthrough.

Official sources

Checked October 2026 against the Illinois Department of Revenue's own publications.

This guide is for general education and reflects rules as of October 2026. Tax law and agency websites change, and your situation may have details that change the answer. Please talk with your tax professional before acting on it.