Each year, millions of donors mail end-of-year gifts to their favorite charities, often sending their checks on December 30 or December 31.

The basic rule on charitable deductions for gifts by mail is that the Internal Revenue Service (IRS) will consider the deduction date as the date shown on the postmark. If the postmark is before December 31, the gift will be deductible for the year 2025.

However, the United States Postal Service (USPS) has adopted a final rule to its Domestic Mail Manual. The change affects Section 608.11 of the manual and clarifies the rules on postmarks. The USPS states, "While a postmark confirms the USPS possessed a mail piece on the date inscribed, that date does not necessarily align with the date the USPS first accepted possession of the item."

The USPS is giving notice that, after December 24, 2025, the postmark may not reflect the date that the check was placed in the mailbox. Instead, the postmark is the "date of the first automated processing operation." It could be one or more days after a customer mails a check when a postmark is stamped on the envelope. The USPS emphasizes "the postmark date is not a perfectly reliable indicator of the date of mailing."

Because millions of donors have historically mailed gifts close to the end of the year and deducted those gifts in the year it was mailed, the new rule may have substantial impact. The USPS offers three solutions that donors should consider for gifts mailed near the end of 2025.

The first is to go to your local post office and request a manual postmark. This will make it clear that the gift was made on or prior to December 31.

A second option is to obtain a "Postage Validation Imprint" (PVI) at your local post office. A USPS employee will apply a PVI label with the date.

The third option is to send the envelope through either Certified or Registered Mail. If the envelope is sent through Certified or Registered Mail, there will be a date and a receipt that indicates the gift was mailed in December 2025.

Donors should be aware that while pre-printed labels from self-service kiosks, Click-N-Ship or postal meters show that the postage was printed on a specific date, this is not the same or accepted as the postmark by the USPS. Donors should mail items early to ensure there is a USPS postmark for the correct year or take the recommended steps to manually obtain a postmark.

The “mailbox rule” remains in effect for donations. The difference after this final rule adoption is that there may be a delay as to when the postmark is affixed, which is the deemed date of mailing. The date of the postmark on an envelope shall be deemed to be the date of delivery for the charitable gift. Therefore, donors who obtain a manual postmark at their local post office can be assured that the gift is valid for 2025.

Editor's Note: End-of-year gifts mailed at the end of December should include a trip to your local post office to ensure receiving a postmark that matches the date of actual mailing. You could also consider making an online transfer which will be dated at the time of the transfer.