New Post Service Rule on Postmarks Effective December 24, 2025

In November 2025, the Postal Service issued a final rule entitled, “Postmarks and Postal Possession,” that became effective as of December 24, 2025. Essentially, the new Rule updates a postmark date, i.e. dropping it in the box, will no longer be considered the postmarked date depending on the location of the mailing due to adjustments to the transportation operations in which it may result in some mailpieces not arriving at originating processing facilities on the same day that they are mailed. This means that the date on the postmarks applied at processing facilities will not necessarily match the date on which the customer’s mailpiece was collected by a letter carrier or dropped off at a retail location.

Overview of the Final Rule:

• The Postal Service is adding section 608.11, “Postmarks and Postal Possession,” to the Domestic Mail Manual (DMM). This new section defines postmarks, identifies the types of Postal Service markings that qualify as postmarks, and describes the circumstances under which those markings are applied.
   
  • It also advises customers of how to obtain evidence of the date on which the Postal Service accepts possession of their mailings.
  • This new language in the DMM does not change any existing postal operations or postmarking practices, but is instead intended to improve public understanding of postmarks and their relationship to the date of mailing.

What this means:

• This is new rule could potentially impact timing of when you mail things, and when they are actually considered mailed:
   
  • Think about court rules that concern the filing of specific documents, state required letters, agency required letters, federal statutes such as the Internal Revenue Service code, state tax statutes and other laws, and numerous election jurisdictions that utilize the postmark to accept certain completed ballots as timely where they are sent by mail but are received after Election Day. Contract and business transactions; insurance claims and premium payments; and sweepstakes, contests and promotions.”)
  • The presence of a postmark on a mailpiece confirms that the Postal Service was in possession of the mailpiece on the date of the postmark's inscription, the postmark date does not inherently or necessarily align with the date on which the Postal Service first accepted possession of the mailpiece. This lack of alignment has and will become more common with the implementation of the Regional Transportation Optimization (RTO) initiative and the corresponding adoption of “leg”-based service standards. (90 FR 10857).
  • Accordingly, the Rule advises customers to request a manual (local) postmark at a retail location if they want to ensure that their mailpiece receives a postmark containing a date that aligns with the date on which the Postal Service first accepted possession of their mailpiece, and reminded customers who wish to retain proof of the date on which the Postal Service first accepted possession of their mailpiece(s) of the services (including Certificates of Mailing) that provide such proof.
  • New definition of postmark: A postmark is a marking applied by the Postal Service to a mailpiece. If applied at a retail unit, the postmark displays the name or location of the retail unit and the date on which the mailpiece was accepted at the retail unit. If applied at a processing facility, the postmark displays the name or location of the processing facility and the date of the first automated processing operation performed on that mailpiece. Where necessary, a postmark also cancels postage so that it cannot be reused.
    

Link to the Final Rule: 

Federal Register :: Postmarks and Postal Possession

Link to USPS Statement:

Postmarking Myths and Facts - Statements - Newsroom - About.usps.com