How to Pay Illinois Estimated Taxes Online: MyTax Steps and Deadlines

To pay Illinois estimated taxes online, go to MyTax Illinois at tax.illinois.gov, choose the option to make an IL-1040 estimated payment, enter your taxpayer and bank information, and submit. You do not need a registered account. Bank transfers through the portal are free; credit card payments go through third-party processors that charge a convenience fee.¹

Estimated payments are quarterly installments toward your Illinois income tax. You generally owe them if your 2026 Illinois liability will exceed $1,000 after withholding and credits, which is common for self-employed workers, landlords, retirees with pension income, and investors.²

What to Have Ready Before You Start

Gather these items before you open the portal. Missing one will stop you partway through:

Your Social Security Number. Businesses use a Federal Employer Identification Number instead.
Your Illinois PIN (IL-PIN). You can look it up on MyTax Illinois using your SSN plus either your Illinois driver’s license number or your prior-year adjusted gross income.
Your bank routing number (nine digits) and account number for the account you want debited.
The dollar amount you plan to pay, from your IL-1040-ES worksheet.

The name on your bank account should match the name on your Illinois tax record. A mismatch can delay processing or cause the payment to be rejected.¹

Step-by-Step Through MyTax Illinois

Guest payments are available, so a full account is optional. The flow is short:¹

Go to tax.illinois.gov. Under the Individuals section, choose Make a Payment, then select “Make an IL-1040, IL-1040-ES, or IL-505-I payment.”
If you do not know your IL-PIN, use the lookup tool. Enter your SSN plus your driver’s license number or prior-year AGI, then note the PIN.
Enter your SSN and IL-PIN on the taxpayer information screen and continue.
Under Payment Types, pick “IL-1040 Estimated Payment.” Set the tax year to 2026 and select the quarter you are paying.
Enter your bank routing number, account number, the date you want the debit to occur, and the payment amount.
Review everything on the confirmation screen. This is your last chance to catch a typo in the bank details.
Submit to authorize the debit.

A registered MyTax Illinois account is worth setting up if you want to see payment history, check your balance, and manage multiple tax types from one place. For a one-off quarterly payment, guest access is enough.

Deadlines for 2026

Illinois follows the federal quarterly schedule. For calendar-year filers, the 2026 due dates are:²

First quarter: April 15, 2026
Second quarter: June 15, 2026
Third quarter: September 15, 2026
Fourth quarter: January 15, 2027

When a due date falls on a weekend or state holiday, the deadline shifts to the next business day. Fiscal-year filers adjust these dates to their own tax year. When scheduling the debit in MyTax Illinois, pick a payment date on or before the deadline; the debit itself may hit your bank one to three business days later.

Paying by Credit Card Instead

Illinois accepts estimated tax payments by credit card through approved third-party processors. The state does not set or receive the convenience fee. As of 2026, the processors and their fees are:³

ACI Payments, Inc.: 2.25% of the payment (minimum $2.50)
payILtax (Catalis): 2.25% of the payment (minimum $3.75)
Link2Gov (FIS): 2.35% to 2.49% of the payment (minimum $2.79)

On a $2,500 payment, those fees add roughly $56 to $62. The bank-transfer path through MyTax Illinois is free, so credit card payment mainly makes sense if you need to float the balance on your card.

When Electronic Payment Is Required

If your annual Illinois individual income tax liability is $200,000 or more, you must pay electronically, either by bank transfer or credit card. A paper check is not an option at that level. Most people making estimated payments fall well below the threshold, but if you meet it, plan on using the online portal.⁴

Using a Prior-Year Overpayment Instead of Sending Money

If you overpaid on your 2025 Illinois return, you can apply part or all of that overpayment to your 2026 estimated taxes rather than take it as a refund. You make the election on Line 40 of Form IL-1040 when you file. You can also split it: refund some, carry the rest forward, as long as the two amounts equal the total overpayment.⁵

The credit is treated as paid on the original due date of the prior-year return, which is April 15 for calendar-year filers, provided you file that return by its extended due date. A carryforward from your 2025 return therefore counts as a payment made on April 15, 2026, covering your first-quarter installment. If any part of the overpayment came from a payment you made after the original due date, that portion is treated as paid on the date you actually made it.⁵

To direct the credit to a tax period other than the default, send a written request to the Illinois Department of Revenue at PO Box 19023, Springfield, IL 62794-9023 when you file. Include your name, SSN, the tax period that produced the overpayment, and the tax period you want the credit applied to.

Save the Confirmation

MyTax Illinois generates a confirmation number on screen once you submit. Print or save the confirmation page right away. It is your proof of timely payment until the transaction shows up on your bank statement. The debit typically posts within one to three business days, so keep enough in the account to avoid an overdraft.¹

When you file your 2026 IL-1040, you will report the total of your estimated payments on the return. You do not need to attach electronic confirmations, but hold on to them. If the Department of Revenue ever questions the timing or amount of an installment, those records are what settle it.²

1
Illinois Department of Revenue. Pay Your Illinois Taxes Online
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Illinois Department of Revenue. IL-1040-ES Estimated Income Tax Payments for Individuals 2026 Instructions
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Illinois Department of Revenue. Pay by Credit Card
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Illinois Department of Revenue. Who Must Make Electronic Payments?
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Illinois Department of Revenue. Step 11 – Refund or Amount You Owe