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Tax Alert: USPS Postmark Changes Could Impact Tax Deadlines

By Arcie Rojas, MBA

January 30, 2026
Current image: Image of a post office sorting mail

If you plan to mail anything time-sensitive to the IRS, California Franchise Tax Board (FTB), or any other government agency, such as your tax return or a payment, there’s an important United States Postal Service (USPS) change you should know about — especially if you tend to cut it close to the deadline with mailing.

On December 24, 2025, the USPS updated its rules so that mailings are now postmarked when they reach a regional processing center, NOT when you drop them in a mailbox or hand them to your local post office. That means the official date stamped on your envelope could be days later than when you actually mailed it.

Why Does This Matter?

Tax agencies used to rely on the postmark date to decide whether your return or payment was filed on time. Under the new system, with the postmark date now being the stamped date from the regional center, something you think you mailed “on time” could end up “late” — and that can lead to penalties, interest, or processing delays.

The California FTB has already flagged this as a real risk and is urging taxpayers to rethink last-minute mailings.

How Can You Protect Yourself?

  • E-file and pay online whenever possible — it’s instant, date-stamped, and skips mail delays altogether.
  • If you need to mail, send things several days early.
  • For extra peace of mind, take your envelope inside a post office and ask the clerk for a manual (local) postmark when you hand it over. This ensures the postmark date matches the day you mailed it — and it’s free.
  • Use Certified Mail, Registered Mail, or a Certificate of Mailing if you want documented proof of the mailing date.

As a reminder: even if you file an extension, any tax owed is still due by April 15.

Bottom line – the mailbox will not be as deadline friendly as in the past. File early, file electronically, or get a manual postmark to save stress — and potentially money — down the line.

Have More Questions?

Check out the USPS’s Postmarking Myths and Facts page. Please discuss any other concerns with your advisor or contact our team for assistance in ensuring timeliness. We’re here to help make this tax season as easy as possible.