New USPS postmark updates could affect timeliness of tax return filings.
If you’ve ever sprinted to the mailbox on April 15 to get your tax return in on time, you may need to plan ahead. (Not that waiting until the last minute is ever a great idea!)
On Dec. 24, 2025, the U.S. Postal Service (USPS) updated its postmark dating procedures to clarify when an item is considered officially accepted. USPS is not changing the current machine application of postmarks; rather, the postmark date now indicates when the mail was first processed at a regional postal facility — not the date it was dropped off.
Why does this specifically matter for tax filings? The U.S. Internal Revenue Code (IRC) §7502(a)(1) is clear: The IRS will rely on the postmark date applied to an envelope to determine timely filing if the document is not physically delivered to the IRS office by the due date.
What does this mean for tax filings? The postmark date applied at USPS processing facilities will not necessarily match the date on which the mail was collected by a letter carrier, dropped off at a retail location, or placed in a collection box — it could be later than the date it was first accepted by USPS. So, if you give your tax filing envelope to your carrier on a Tuesday afternoon, it may not make it to the regional processing center to be postmarked that Tuesday. USPS is making changes to its transportation operations, necessitating the update.
Is there any guarantee a letter is postmarked by a certain date? Yes, USPS offers an option to ensure the postmark date aligns with the mailing date, but you need to proactively go in person to any USPS retail counter and ask the piece to be manually postmarked (also called “hand-canceling). USPS offers this as a free service up to 50 items. Other options include purchasing a certificate of mailing or using registered or certified mail to obtain a receipt showing the date of acceptance.
What about printed postage that has a date on it? If you apply a pre-printed label, such as from home or a self-serve kiosk, you are still not guaranteed that date matches the date USPS first processes the item.
What should taxpayers do to make sure the IRS receives tax filings on time? Here are ways you can protect yourself from a late filing:
- Work with your CPA. As trusted tax preparers, CPAs will work with you to ensure your filing is received by the IRS on time.
- Choose certified or registered mail. Yes, this requires paying extra ($5.30 for certified, $4.40 for mail receipt or $2.82 for email receipt), but the piece of mind could be worth it. You will also have to go to a USPS retail location in person. It’s a good idea to choose certified or registered mail for any correspondence with the U.S. government so that you have a printed record.
- Mail early. If choosing certified or registered mail is not an option, aim to put your tax filing in the mail at least five days before the deadline (or even earlier).
Does the USPS have any guidance? Sure does. Check out these links for more information: