New USPS Postmark Rules Don’t Change IRS Rules

The U.S. Postal Service (USPS) issued final rules adding a new section on postmarks to its operating manual. According to the rules’ preamble, the new section of the operating manual does not represent “a change to existing postal operations or postmarking practices but instead is intended to improve public understanding of postmarks and their relationship to the date of mailing.” The preamble and the rules explain that the postmark date does not always align with the date the post office first takes custody of the mail piece and that this lack of alignment will become more common as post office operations become more centralized. The rules also explain that customers can go to their local post office and ask the representative to put a postmark on the mail piece when the representative accepts it at the counter.

In most cases, a USPS postmark can be relied upon to determine whether a tax payment or filing is timely. However, a taxpayer that solely relies on the postmark date runs the risk of missing a payment or filing deadline. The good news for taxpayers is that there are ways to get more certainty about the date a tax payment is made or a tax document is filed.

Crowe observation
Although the federal government has announced that it no longer will be accepting payment by paper check, the IRS will continue to accept paper checks as payment.

Date of delivery

Under IRC Section 7502(a), if the IRS receives a payment or document and the postmark date on the envelope is on or before the due date and actual receipt by the IRS is after the due date, that payment or document generally will be treated as mailed on the postmark date (other requirements apply, such as using U.S. mail and addressing the envelope properly). States have similar rules, but it is important to confirm the specific rule for each relevant state.

IRC Section 7502(a) applies only if the IRS is in actual receipt of the payment or filing. For instance, if a taxpayer walks into a post office on April 15, 2026, the due date for their 2025 federal income tax return, and the postal representative at the counter stamps the envelope with a postmark dated April 15, 2026, the postmark is proof of mailing the return on April 15, 2026, only if the envelope is delivered. If the envelope gets lost between the post office and the IRS, the postmark is of no help in showing the date that the taxpayer mailed the return.

In the limited cases where a federal deposit is made by paper check, IRC Section 7502(e) generally requires that the deposit be mailed in the U.S. at least two days before the due date for the rules regarding date of delivery to apply.

Proof of delivery

Under IRC Section 7502(c), sending a tax payment or document by USPS certified or registered mail is prima-facie evidence of delivery, even if the IRS has no record of receiving it. Many states have similar rules, but it is important to check the specific state rules to be sure whether and how they apply.

While not required to meet the requirements of IRC Section 7502(c), requesting a return receipt can be helpful if the IRS has no record of receiving the payment or document. Some states require a return receipt for proof of delivery.

Crowe observation
Saving a copy of the signed and dated document or payment also can be helpful when the tax authority has no record of receiving the payment or document.

A taxpayer also can meet federal proof of delivery requirements by using a private delivery service (PDS) specifically designated by the IRS as a PDS for purposes of IRC Section 7502(f). While most private delivery companies have services designated by the IRS as qualifying for proof of delivery under IRC Section 7502(f), taxpayers need to check the IRS list carefully to verify that the particular delivery service they are using is included on the list. A recent court case found that the taxpayer’s document was not timely filed because, although they used a private delivery company with services included on the IRS’ list, the particular service that the taxpayer used was not on the list.

Taxpayers using a PDS also should make certain that they use the proper IRS address. The address for PDS deliveries can differ from the address for USPS mail deliveries.

Electronic payment and filing

Timeliness rules also apply to electronic filing and payment. Generally, under IRC Section 7502(c)(2) and the regulations thereunder, receipt of a return acknowledgement from tax filing software is treated as an electronic postmark for purposes of determining the date of filing and provides proof of filing. However, taxpayers and practitioners must carefully evaluate messages received from the software after submitting a return for electronic filing because the return might not have been accepted by the tax authority due to an error. Generally, tax authorities provide a limited number of days during which errors can be fixed and resubmitted and still be treated as filed on the date the return was first attempted to be filed (perfection period). Perfection periods vary by type of return and tax authority.

The IRS offers numerous electronic payment methods, including ACH debit and the electronic federal tax payment system (EFTPS). The EFTPS is required to be used by businesses and certain other taxpayers. Electronic payments might not be credited in IRS systems on the date the taxpayer initiates the transaction, so initiating an electronic transfer of funds a few days before the due date can help to prevent late payment.

Looking ahead

While the newly released USPS operating rules caught the attention of the public, they don’t change best practices for timely paying taxes or filing returns. While a postmark date will be treated as the date of mailing for federal and most state tax purposes, that rule only applies if the mail piece is delivered and provides no protection to the taxpayer if the IRS or state tax authority has no record that it received the payment or document. Therefore, taxpayers should consider using options, like USPS certified mail or electronic filing, so they can prove timely payment or filing.