If you’ve ever dropped something into a big blue mailbox at 11:59pm and thought, “Boom, deadline met,” the U.S. Postal Service would like a word.
A clarification that took effect on December 24, 2025, spells out something USPS says has long been true in practice: the date on your envelope’s postmark is tied to when your mail gets processed, not necessarily when you dropped it off. In the updated rules (added to the Domestic Mail Manual as section 608.11), USPS says the postmark date reflects the first automated processing operation—or the date it’s accepted at a retail counter.
The dumbed-down version: you can mail something “on time” and still get a postmark that looks late.
That matters because a lot of real life still runs on postmarks. Think: tax returns, court paperwork, rent checks, insurance stuff, charity donations and any bill payment where “postmarked by” is the rule. If the postmark lands after the deadline, you could face late fees, penalties or paperwork drama. AARP also warns that the gap between drop-off and postmark dates may become more common as USPS consolidates processing.
Ballots are the big one people worry about, because some states accept mail ballots that arrive after Election Day as long as they’re postmarked by the deadline. The Postal Service’s own guidance says if you want to make sure your ballot gets a postmark that matches the day you mailed it, you should take it to a post office retail counter and request a manual postmark.
So what should you do? First, mail time-sensitive stuff earlier than you think you need to. “Day of” is now playing with fire. You can also go inside the post office and ask for a manual postmark if the date is critical. And for extra proof, use services that create a paper trail (like Certified Mail) or consider filing online when that’s an option.
One more 2026 note: shipping rates for services like Priority Mail and USPS Ground Advantage are scheduled to increase on January 18, 2026, while the First-Class stamp remains at $0.78—for now.