To pay Illinois state taxes, you have four options: an electronic payment through the MyTax Illinois portal, a credit card payment through a third-party processor, an automated phone payment, or a check or money order mailed with Form IL-1040-V. Illinois charges a flat 4.95% income tax, and the balance is due April 15 for calendar-year filers.
What to Have Ready Before You Pay
Every method needs your Social Security number or Individual Taxpayer Identification Number, the exact tax year the payment covers, and the exact amount you owe. If the payment is for a business entity, use the Federal Employer Identification Number instead.
For mailed payments, you also need Form IL-1040-V, the individual income tax payment voucher. It asks for both spouses’ full legal names on a joint return, Social Security numbers, and a “tax year ending” date.1Illinois Department of Revenue. 2025 IL-1040-V Payment Voucher for Individual Income Tax The voucher is what links your check to your return, so a wrong Social Security number can send the money to the wrong account or generate a notice from the Department of Revenue.
Paying Online Through MyTax Illinois
The fastest and cheapest way is at mytax.illinois.gov. On the main page, choose “Make a Payment,” then select “Individual Income Tax.” You can pay directly from a checking or savings account using your bank’s routing number and account number.2Illinois Department of Revenue. Payment Options for Individuals The system issues a confirmation number when you submit; save it as your receipt.
You don’t need an account for a one-time payment. The portal has a guest payment option on its homepage. If you do register, the same dashboard shows payment history, balance owed, and installment plan setup.
Paying by Credit Card or Phone
Illinois takes credit card payments through three third-party processors. Each charges a convenience fee running 2.25% to 2.49% of the payment amount, with minimum charges of $2.50 to $3.75.3Illinois Department of Revenue. Pay by Credit Card On a $5,000 balance that’s roughly $112 to $125 in fees, so a bank transfer through MyTax Illinois is cheaper whenever it’s an option.
For an automated phone payment, call the Department’s Pay-by-Phone line at (866) 490-2061. The system walks you through authorizing an electronic withdrawal from a checking or savings account.4Illinois Department of Revenue. CPP-1 Installment Payment Plan Request Credit cards aren’t accepted over the phone.
Mailing a Check or Money Order
The address depends on whether the voucher travels alone or with a paper return.
If you’re mailing just the IL-1040-V with a check (no return enclosed):
Illinois Department of Revenue
Springfield, IL 62726-0001
If you’re mailing the voucher together with your paper Form IL-1040:
Illinois Department of Revenue
PO Box 19027
Springfield, IL 62794-90275Illinois Department of Revenue. Mailing Addresses
Make the check or money order payable to “Illinois Department of Revenue.” Write your Social Security number and the tax year directly on the payment. When you send the voucher with your paper return, staple the check and voucher to the front of the IL-1040.6Illinois Department of Revenue. 2025 Form IL-1040 Instructions That’s the opposite of the usual “don’t staple your payment” instruction from other agencies, but the Department’s processing equipment is built for it.
Deadlines and What Late Costs You
April 15 is the deadline for calendar-year filers to both file and pay.7Illinois Department of Revenue. Due Date/Extension to File Income Tax Return The late-payment penalty jumps sharply once you cross 30 days:
- 1 to 30 days late: 2% of the unpaid tax.
- 31 or more days late: 10% of the unpaid tax.
- Higher penalties (15% and 20%) apply if the amount remains unpaid after an audit begins or concludes.8Illinois Department of Revenue. Publication 103 – Penalties and Interest for Illinois Taxes
Interest runs on top of penalties. Through at least June 30, 2026, the rate is 7% per year, adjusted semiannually to track the federal underpayment rate.9Illinois Department of Revenue. Interest Rates If a late payment is unavoidable, getting it in before day 31 saves the most.
An Extension to File Is Not an Extension to Pay
Illinois gives you an automatic six-month extension to file, moving the return deadline to October 15. Payment is not extended. Any tax owed is still due April 15, and interest and penalties start on that date if the balance isn’t paid.7Illinois Department of Revenue. Due Date/Extension to File Income Tax Return
If you know you’ll owe but aren’t ready to file, submit Form IL-505-I with your best estimate by April 15. You can send it through MyTax Illinois or by mail. A reasonably accurate estimate protects you from the late-payment penalty even when the return itself comes in months later.
If You Can’t Pay the Full Balance
The Department accepts installment plans. The simplest way to request one is inside MyTax Illinois: log in and choose “Set up a Payment Installment Plan with IDOR.” You can also mail a paper Form CPP-1.10Illinois Department of Revenue. Electronic Payments and Payment Plans
A good-faith down payment goes with the application. There’s no fixed minimum, but the Department encourages making it as large as you can, because interest keeps accruing on whatever remains.4Illinois Department of Revenue. CPP-1 Installment Payment Plan Request If your unpaid liability exceeds $10,000, attach a financial disclosure statement (Form EG-13-I for individuals or EG-13-B for businesses).
Two things surprise people about installment plans. First, penalties and interest keep running the whole time; the plan stops collections activity but doesn’t freeze your balance. Second, the plan is conditional. Miss a scheduled payment or fail to file a future return on time, and the agreement can be terminated, which reopens the full balance to collections. Monthly payment amounts and plan length are set based on your financial condition rather than a formula, so the Department has room to work with what you can actually afford.
Quarterly Estimated Payments
If you expect to owe more than $1,000 in Illinois income tax after withholding and credits, quarterly estimated payments are required through the year.11Illinois Department of Revenue. Pub-105 – Estimated Payments Requirements for Individuals and Businesses This mostly hits self-employed workers, freelancers, landlords, and anyone with investment income that isn’t withheld at the source.
Calendar-year due dates for tax year 2026 are April 15, 2026; June 15, 2026; September 15, 2026; and January 15, 2027.12Illinois Department of Revenue. 2026 IL-1040-ES Estimated Income Tax Payments for Individuals
You can pay estimates through MyTax Illinois, by phone, or by mailing a check with Form IL-1040-ES. Note the mailing address for estimates differs from the annual return address:
Illinois Department of Revenue
Springfield, IL 62736-00015Illinois Department of Revenue. Mailing Addresses