With tax season already upon us, you might be using this time to start getting your documentation and tax forms in order. This is also a good time to review any changes that were made to tax laws and codes within the past year, especially with passage of the One Big Beautiful Bill Act (OBBBA) that resulted in many new tax provisions.
One change you won't want to overlook that actually has nothing to do with OBBBA but could affect your taxes? A recent change implemented by the United States Postal Service (USPS) as it relates to postmarking mail.
A Quick Explanation of What's Changed
Beginning December 24, 2025, the USPS announced that postmarks will now show the date your mail has first been processed by a sorting facility. In the past, a postmark always reflected the exact day that you dropped your mail off. With this new change in place, however, your mail may not be postmarked until several days after you put it in the mailbox or drop it off at the post office.
How the Change Could Affect You
You might be wondering, “Why does this matter?”
For your everyday mail, it probably won't. However, if you're mailing anything that needs to be postmarked by a certain date or deadline, this new policy could have major impacts. This is especially true when it comes to mailing tax forms (such as tax returns) and other important legal documents.
Under the new policy, even if you technically mailed something out before the deadline, it might not be postmarked by your local post office until a few days later. As a result, your postmark could reflect a later date—resulting in your tax filing or other important documentation being treated as late.
For tax returns, a late return could even mean that you accumulate additional penalties and interest—all because the post office didn't postmark your mail on the same day you dropped it off.
What You Need to Know to Protect Yourself
This new policy has the potential to create some major headaches for taxpayers, so it's important that you plan ahead to protect yourself from unnecessary penalties, interest and late fees.
The good news? There are plenty of ways to ensure that your mail isn't considered “late” due to a delayed postmark. One option is to have a USPS employee date-stamp a receipt when you drop it off at the post office. This way, if there are any issues with your mail being postmarked late, you can show proof with your receipt.
Another option? Simply get your mail out a few days earlier, especially if you're mailing something with a time-sensitive deadline. By getting your mail out five days ahead of the official deadline, this should give the USPS plenty of time to get it timestamped.
Unfortunately, the following do not count as proof of postmark because they only show when your postage was printed and not when the USPS accepted the mail:
- Printed postage labels
- Click-N-Ship labels
- Metered postage strips
- Self-service kiosk receipts
Finally, you could consider going another route when it comes to your mail carrier. FedEx and UPS, for example, will still postmark your mail on the same day you drop it off. You might pay more to mail through these services, but if you need the additional peace of mind, it may be worth the additional cost.
A seemingly small change to how USPS processes mail could result in some major problems for taxpayers in the coming tax season, so it's important to plan ahead.
To summarize, mail any physical tax returns or other important tax documents 5-7 days earlier than the actual deadline to protect yourself—or consider asking a postal service worker for a date-stamped receipt. If all else fails, you could always use a different mail carrier service as well.
If you have any questions or would like additional information, please contact our Tax Services team.