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How to Postmark a Letter: USPS Rules and Options
USPS postmark dates no longer match your drop-off date. Learn how to get a manual postmark for free, why it matters for deadlines, and your alternatives.
Read the full guide →USPS Postmark Guide
A USPS postmark is the ink stamp on your envelope showing the date and location where USPS accepted the mail. The postmark date — not the delivery date — is what matters for IRS tax deadlines and legal filing requirements.
Key Facts
Pricing
Postmark vs Postage: What Is the Difference?
Postage is what you pay to mail something. A postmark is the mark USPS applies showing when it was processed. Here is why the difference matters.
Guides
Guide
Postmark Date and Tax Returns: The IRS Mailbox Rule After the 2026 USPS Change
The IRS treats a timely postmark as a timely filing. But USPS postmark dates no longer match your drop-off date. Here is how to protect yourself at tax time.
Guide
Postmark vs Proof of Mailing: What a USPS Postmark Actually Means in 2026
USPS postmarks don’t always equal the day you dropped mail. Here’s what a postmark means in 2026—and how to get real proof of mailing (with the right USPS services).
Frequently Asked Questions
Send USPS Postmark From Your Desk
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