USPS form guide
PS Form 3877: Firm Mailing Book for Accountable Mail
USPS PS Form 3877 is the Firm Mailing Book for Accountable Mail. A mailer presenting three or more pieces with eligible extra services at one time may use a firm sheet instead of the individual receipt portion for every piece. The USPS-postmarked sheet becomes the mailer's mailing record.
Published Aug 10, 2026
Quick answer
Use PS Form 3877 when you are presenting a multi-piece accountable-mail mailing directly to USPS and need one itemized firm sheet. List each article number, recipient, postage, and applicable extra-service fees, then present the pieces and the sheet together for USPS acceptance.
When PS Form 3877 is appropriate
The official form describes use for three or more pieces with extra services presented at one time. It can cover accountable services such as Certified Mail, Registered Mail, insured mail, or Collect on Delivery when the applicable USPS rules are followed.
PS Form 3877 is not just a spreadsheet of addresses. The article numbers and charges on the sheet must correspond to the physical mailpieces USPS is accepting.
What the firm sheet records
- The USPS article or extra-service number for each piece.
- The addressee name and delivery address.
- Postage and applicable extra-service fees.
- Page totals and cumulative totals.
- The mailer's name, address, and mailing date.
- USPS acceptance evidence on the sheet returned to the mailer.
Keep the accepted sheet with your mailing records. USPS instructions warn that, for many uses, the sheet returned to the mailer is the only receipt and USPS does not retain another copy.
Privately printed and computer-generated firm sheets
USPS allows approved privately printed or computer-generated facsimiles that contain the required information and closely match the official form. The form instructions say the local postmaster or Business Mail Entry manager must approve the facsimile in writing. A mailer using a custom version should not assume that a generic spreadsheet is automatically accepted.
Registered Mail and Collect on Delivery can require duplicate copies. Confirm the current Domestic Mail Manual rules and local acceptance process before preparing the mailing.
PS Form 3877 vs. other USPS proof forms
| Form | Best fit | Proof supplied |
|---|---|---|
| PS Form 3800 | One domestic Certified Mail piece | Individual Certified Mail receipt and article number |
| PS Form 3817 | One ordinary piece needing Certificate of Mailing | Proof the piece was presented to USPS, not delivery proof |
| PS Form 3665 | A qualifying multi-piece Certificate of Mailing | Firm certificate for ordinary-mail presentation |
| PS Form 3877 | Three or more accountable or extra-service pieces | Itemized firm mailing receipt for the listed articles |
Do not use PS Form 3877 as a replacement for PS Form 3817 or PS Form 3665 when the service you are buying is Certificate of Mailing. The official PS Form 3877 instructions point Certificate of Mailing users to those forms.
Is PostalForm bulk mailing the same thing?
No. PostalForm's bulk workflow helps prepare and send multiple documents online. PS Form 3877 is a specific USPS acceptance record used when accountable pieces are presented under USPS firm-mailing rules.
Use USPS directly when you need the original firm sheet postmarked at acceptance. Use PostalForm bulk mailing when your job is generating, printing, addressing, and mailing document batches and the PostalForm checkout options meet your proof requirements.
Sources
FAQs
- How many pieces require PS Form 3877?
- The form instructions describe its use for three or more pieces with eligible extra services presented at one time.
- Can I create my own PS Form 3877 spreadsheet?
- USPS permits approved facsimiles, but the form says a privately prepared version requires written approval from the local postmaster or Business Mail Entry manager and must contain the required information.
- Does PS Form 3877 prove delivery?
- The accepted sheet proves USPS received the listed pieces with the recorded services. Delivery evidence comes from the tracking and extra services purchased for each article.
- Is PS Form 3877 the same as Certificate of Mailing?
- No. USPS directs Certificate of Mailing users to PS Form 3817 for an individual piece or PS Form 3665 for qualifying firm mailings.
Ready to send it?
If USPS-postmarked firm-sheet evidence is required, confirm the current form and acceptance process with the Post Office or Business Mail Entry location where you will present the pieces.