USPS Postmark Clarification and Its Impact on Tax Filings

The U.S. Postal Service (USPS) recently updated its operating manual to clarify how postmarks are applied and what they represent. The USPS emphasized that this clarification does not change existing postal operations. Instead, it explains that a postmark date reflects when USPS processes the mail, which may not always match the exact date the Postal Service first takes physical custody of a mail piece.

When a Postmark Counts

Under Internal Revenue Code Section 7502, a tax return or payment is generally considered timely if:

• The IRS receives it after the due date, and
• The envelope bears a USPS postmark dated on or before the due date

This “timely mailing equals timely filing” rule provides meaningful protection. However, it applies only if the IRS actually receives the return or payment. If a document is postmarked on time but lost in transit, a postmark alone may not be sufficient to establish timely filing without additional proof of mailing or delivery.

Certain federal tax deposits made by paper check are subject to additional timing requirements. In limited cases, the payment must be mailed at least two days before the due date for the rule to apply.

States often follow similar standards, but requirements vary. Taxpayers should confirm the applicable rules in each state where they file.

Strengthening Proof of Delivery

Because delivery is critical, taxpayers may want to consider added safeguards when mailing important documents.

• Certified or Registered Mail: Mailing a return or payment by certified or registered mail provides prima facie evidence of delivery under federal law. This documentation can help substantiate timely filing even if the IRS does not have an internal record of receipt.
• Return Receipt: Although not required under federal rules, requesting a return receipt provides written confirmation of delivery. Some states require a return receipt to establish proof.
• Private Delivery Services: Certain IRS-designated private delivery services qualify for proof-of-delivery treatment. Not all services offered by private carriers are approved, so taxpayers should verify that the specific delivery option selected appears on the current IRS-approved list.
• Mailing addresses for private delivery services may differ from standard USPS addresses, and using an incorrect address could affect timely filing treatment.

Recent court decisions highlight the importance of these details. In some cases, filings were considered late because the specific delivery service used was not on the IRS-approved list.

Electronic Filing and Payment Options

Electronic methods can provide greater certainty than traditional mail.

For electronically filed returns, an acknowledgment from tax software generally serves as proof of submission. Taxpayers should review confirmation messages carefully to ensure the return was accepted. If rejected due to errors, tax authorities typically allow a limited period to correct and resubmit while preserving the original filing date.

The IRS also offers several electronic payment options, including ACH debit and the Electronic Federal Tax Payment System (EFTPS). Because electronic payments may not be credited the same day they are initiated, scheduling payments several days before the deadline can help prevent late-payment issues.

The Bottom Line

The USPS clarification does not change IRS filing rules, but it reinforces an important point. A postmark can establish a mailing date only if the return or payment is ultimately delivered.

Certified mail, approved private delivery services, and electronic filing methods can provide stronger documentation and reduce risk. At LMC, we help clients implement practical procedures to ensure tax filings and payments are submitted accurately and on time.

If you have questions about mailing requirements or electronic filing options, contact an LMC professional.