USPS Postmark Guide

What a USPS postmark shows, when the date is the day you mailed it, and what actually proves mailing for tax and legal deadlines.

ARTICLES

Editorial illustration of envelopes, a red letter sorter and bundled correspondence.

POSTMARK · March 14, 2026

How to Postmark a Letter at a USPS Counter

Hand your letter to a USPS clerk and ask for a manual postmark: it is free and dated that day. What to say, why drop-box dates slip, and which receipt to keep.

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