10/19/2026
Mailing Your Tax Return? “Postmarked on Time” Isn’t What It Used to Be
For decades, a tax return postmarked by the deadline was treated as on time. That rule hasn't changed — but the Postal Service has changed what a postmark date means, and dropping an envelope in a mailbox on deadline day is now riskier....
New USPS rules mean a postmark may be dated days after you mail your return. Here's how to protect your filing date and avoid late-filing penalties.