PS Form 3817 is the USPS Certificate of Mailing for an individual mailpiece. Fill in the sender’s name and address in the “From” section and the recipient’s name and address in “To.” The certificate provides evidence that the item was presented to USPS for mailing. It does not establish that the recipient received the item, signed for it, or read its contents. [1]
Rules that determine the answer
USPS mailing standards require the certificate to be presented at the time of mailing, completed legibly, and returned to the mailer after postal postmarking. The Postal Service does not retain a copy. Form 3817 is for fewer than three individual pieces presented together; the firm-sheet process uses Form 3665 for three or more pieces, subject to its rules. Correct postage is required in addition to the certificate service fee. [2]
Choose the service to match the requirement. Certified Mail, a Return Receipt, tracking, and a Certificate of Mailing serve different purposes; the cheapest proof of mailing may not satisfy a contract, statute, or court’s service rule. [2] Keep a copy of the document and a record connecting it to the mailing, while recognizing that your copy does not transform the certificate into USPS verification of contents. A duplicate certificate after mailing requires the original postmarked certificate under the applicable procedure. [2]
What to do next
- Address and prepare the mailpiece, then copy the sender and recipient information accurately onto Form 3817 in the permitted legible format.
- Bring the item and certificate to the retail postal counter at mailing time and request Certificate of Mailing service. Do not simply leave an unstamped certificate in a mailbox.
- Pay postage and the applicable certificate fee, leaving the designated postal postmark area for USPS.
- Before leaving, check that the returned certificate has the postmark and correct address details. Keep the original securely and scan a backup for your records.
Practical example
A sender mails a routine notice and obtains a postmarked Form 3817. If a later dispute concerns whether the notice was mailed on time, the certificate can help document presentation for mailing. If the dispute instead concerns delivery, a recipient signature, or exactly which document was inside, the certificate alone does not answer those questions.
For related situations, see who may sign for Certified Mail and serving court papers through USPS.
Primary sources
- USPS PS Form 3817: sender, addressee, fee, and postmark fields
- USPS Domestic Mail Manual 503.5: certificates, preparation, acceptance, and duplicates
Sources checked: October 31, 2026.