Totally off my radar until I saw a LinkedIn post by April Clark. Starting December 24, 2025 your local post office will no longer postmark outgoing mail. The postmark will be places on the mail by the regional post office and that may occur days after it was put in the mail.
Clark pointed out that any donations mailed at the end of 2025 may need to be credited to 2026 based on the postmark date. IRS rules tie the date of the donation to the date of the postmark.
This will impact other activities which tie validity to the date of postmarks including tax returns, mailed ballots, etc.
A Forbes article on the topic suggests mailing things in person and taking explicit steps to make sure the postmark is the date of the mailing.
Buy postage at the counter. When a customer pays for postage at a retail counter, the Postage Validation Imprint (PVI) label stamped on the mailpiece indicates the date of acceptance.
Ask for a manual postmark. Customers who want a postmark dated when the Postal Service first accepted possession of their mailpiece may, for no extra charge, request a manual postmark at any Post Office, station, or branch….
Purchase a Certificate of Mailing. If you want proof of the date on which the USPS first accepted possession of the mailpiece, you can purchase a Certificate of Mailing….
[…]
But beware: Pre-printed labels, including postage printed from Self-Service Kiosks, Click-N-Ship online postage, and meter strips, only show that you’ve bought and printed postage. They do not prove that the USPS accepted the mailpiece.
Certified and registered mail are other options.
One of the things non-profits are probably going to need to do going forward is encourage people to either use online giving channels or mail their donations extra early if they aren’t going to visit the post office to mail things in person.
