GLOSSARY
Certificate of Mailing
By Justin Winter · Updated August 28, 2026
A USPS receipt proving you mailed a specific piece on a specific date. It does not track the piece and it does not prove delivery.
A Certificate of Mailing is the cheapest evidence USPS sells: a stamped record that a piece was accepted on a date. There is no tracking number, no delivery scan, and no signature.
It is enough when a rule only requires that something was sent by a deadline — a postmark-date argument. It is not enough when you need to show the piece arrived.
See also
- Certified Mail — A USPS extra service that adds a dated mailing receipt and delivery tracking to a letter, with the delivery record kept by USPS.
- Proof of mailing — Documentation that a piece of mail was handed to USPS on a given date — the sending half of the evidence, not the delivery half.
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