U.S. Postal Service (USPS) quietly changed its postmark rule effective December 24, 2025, clarifying that a machine postmark shows the date of the “first automated processing,” not necessarily when you dropped the mail off, which can be days later, impacting deadlines for taxes, ballots, and legal documents.

To ensure your mail is postmarked the actual date of deposit, you must request a free, manual hand-stamped postmark at a USPS counter or use Certified/Registered Mail, as machine stamps may be delayed due to network consolidation.

What changed?
Old understanding: A postmark reflected when you dropped mail in a box or at the counter.
New rule: The date on a machine postmark is when it first enters the automated sorting system at a regional facility, which could be days after you deposited it.

Why does it matter?
Deadlines: Federal and state laws often rely on the postmark date for timely filing of taxes, votes, and legal papers, potentially leading to late penalties.
Example: A tax payment dropped off on Dec 31 might get postmarked Jan 2, making it late for the Dec 31 deadline.

How to ensure an on-time postmark:
Go inside: Visit a USPS retail counter and ask the clerk for a manual (hand-stamped) postmark for free.
Use secure services: Send items via Certified Mail or Registered Mail for dated proof of mailing.
Mail early: Send time-sensitive items well before the deadline to allow for processing delays.