Form IL-1040-V is the one-page payment voucher Illinois residents mail with a check or money order to pay the balance due on their IL-1040 Individual Income Tax Return. Download the current year’s version from the Illinois Department of Revenue (IDOR) website, fill in a handful of fields, and send it with your payment to Springfield by April 15.1Illinois Department of Revenue. Due Date/Extension to File Income Tax Return (2025 IL-1040) If you’d rather pay online, IDOR offers electronic options that skip the voucher entirely.
Download the Right Year’s Voucher
Use the voucher that matches the tax year you’re paying for. Submitting the wrong year’s form can cause IDOR to apply your payment to the wrong period. The current PDF is on the IDOR website.2Illinois Department of Revenue. Where Can I Find Form IL-1040-V to Mail in My Payment?
Filling In the Fields
The voucher is short. Print legibly — IDOR processes a huge volume of paper during filing season, and unclear handwriting slows things down or triggers errors.3Illinois Department of Revenue. Form IL-1040-V Illinois Payment Voucher You’ll need to enter:
- The primary filer’s Social Security number, and the spouse’s SSN if filing jointly. These are the most important entries on the voucher; a wrong digit can send your payment into someone else’s account.
- Your first name and initial, plus your spouse’s if applicable, exactly as they appear on your IL-1040.
- Your current mailing address — street, city, state, and ZIP. Keep it consistent with the address on your return.
- The payment amount, written as dollars and cents with no dollar signs or extra symbols. This is the balance due from your IL-1040.
Mailing the Voucher and Your Payment
Make your check or money order payable to “Illinois Department of Revenue.” Write your Social Security number on the check itself as a backup identifier in case the voucher gets separated during processing.3Illinois Department of Revenue. Form IL-1040-V Illinois Payment Voucher Do not staple or clip the check to the voucher; automated scanning equipment handles them separately. Place both items loose in the envelope and mail to:
Illinois Department of Revenue
Springfield, IL 62726-00013Illinois Department of Revenue. Form IL-1040-V Illinois Payment Voucher
Making Sure Your Postmark Counts
A mailed payment is on time if the envelope is postmarked by April 15, even if IDOR receives it later. But a USPS rule change effective December 24, 2025, makes postmark dates less predictable. Under the new processing system, the postmark is applied when mail reaches an automated sorting facility rather than when the Postal Service first takes possession of it. A letter dropped in a blue collection box could receive a postmark one to three days after the actual deposit date, which can push a timely payment past the deadline on paper.4Taxpayer Advocate Service. New U.S. Postal Service Rules Could Affect Whether Your Tax Filing Is Considered On Time
To protect yourself, bring the envelope to a post office counter and ask for Certified Mail or a manual postmark. A manual postmark is free if you already have postage. Pre-printed meter stamps and online-printed postage labels do not count as proof of your mailing date. Certified Mail costs a small fee but gives you a dated receipt and tracking, which is the strongest evidence you’ll have if a penalty dispute comes up later. Keep the receipt; USPS does not store a copy for you.5USPS. Mail Your Tax Return with USPS
If You’d Rather Pay Electronically
The voucher is only needed for paper payments. IDOR offers three electronic options that make IL-1040-V unnecessary:6Illinois Department of Revenue. Make a Payment – Options for Individuals
- MyTax Illinois, paying directly from a checking or savings account. You don’t need an existing MyTax account; a guest payment option works for one-time use.
- Credit or debit card, online or by phone. The card service provider charges a convenience fee on top of your tax.
- ACH credit through your bank. IDOR describes this option as better suited to recurring or business payments rather than a one-time individual payment.
Electronic payments post faster, remove the risk of a lost envelope, and avoid the postmark timing issue above.
If Your Payment Arrives Late
Paying late triggers a penalty on the unpaid tax. One to 30 days late is a 2% penalty; after 30 days, the rate rises to 10%.7Illinois Department of Revenue. Pub-103, Penalties and Interest for Illinois Taxes Simple interest also accrues daily from the day after the payment was due until you pay.8Illinois Department of Revenue. How Is Interest Calculated and What Is the Current Interest Rate
Records to Keep
Hold on to your completed voucher, a copy of the check or money order, and any mailing receipts. Illinois requires taxpayers to keep records supporting a return for three and a half years after filing. If IDOR later issues a Notice of Tax Liability or disputes your payment, keep everything related to that period until the matter is fully resolved, even if that stretches past the three-and-a-half-year window.9Illinois Department of Revenue. Pub-113, Keeping Complete and Accurate Records A Certified Mail receipt is particularly useful because it documents both the mailing date and the date IDOR received the envelope.