USPS Clarifies Postmark Rules for Timely Mail

The U.S. Postal Service has clarified its definition of postmarks in a recent update to its mailing standards, a change that could impact the timeliness of items such as mail-in ballots, tax returns and bill payments. The rule, published in the Federal Register on November 24, 2025, and effective December 24, 2025, adds a new section to the Domestic Mail Manual outlining how postmarks indicate when the agency takes possession of mail.

Under the updated guidance, a postmark serves as the official mark confirming U.S. Postal Service possession of a mail piece, but it does not always correspond to the date the item was dropped off at a mailbox or handed to a carrier. Instead, most machine-applied postmarks reflect the date when the mail is processed at an automated sorting facility. According to the Postal Service, mail collected from boxes or counters may be transported overnight or across regions before reaching these facilities, potentially resulting in a postmark date one or more days after deposit.

The Postal Service emphasized that this clarification does not alter how postmarks are physically applied. It stems from operational adjustments under the agency's broader...