USPS Certified Mail: what it is, what it proves, and how to send it

Certified Mail is a USPS extra service added to a First-Class or Priority Mail letter. It gives the sender a mailing receipt with a tracking number, and the Postal Service records the delivery or the delivery attempt; add a return receipt and you also get the signature and name of whoever accepted it. It does not make the letter faster, and it does not prove what was inside the envelope. You can send it at a Post Office counter, or from home through a print-and-mail service such as Piloxa, which also keeps the exact document you sent.

Certified Mail, fact by fact

Each fact below has its own address, so it can be linked to on its own (for example piloxa.com/certified-mail#certified-mail-cost). USPS facts cite the Domestic Mail Manual, the Postal Service’s own rulebook; prices are the USPS schedule effective July 12, 2026.

What Certified Mail is

Certified Mail is a USPS extra service, not a mail class. It is added to a First-Class Mail or Priority Mail piece and gives the sender a mailing receipt and an electronic record of delivery or attempted delivery. It does not make the letter travel faster. Source: DMM 503, Extra Services.

What it proves

That a mailpiece with that article number was accepted by USPS on a date, and was delivered, or delivery was attempted, at the address on a date USPS recorded. With a return receipt it also shows to whom it was delivered and the delivery address. Does Certified Mail prove delivery?

What it does not prove

What was inside the envelope. USPS records the mailpiece, not the document in it, and no Certified Mail record names the contents. It also does not prove the named person read the letter: anyone authorized to receive the addressee’s mail can sign. Proving contents takes a separate record, such as a kept copy of the exact document tied to the article number. Proving what was in the envelope.

Certified Mail cost in 2026

The Certified Mail fee is $5.55, on top of postage: $0.82 for a one-ounce First-Class letter with a stamp, so $6.37 at a Post Office counter. With the electronic return receipt ($2.91) it is $9.28; with the paper green card ($4.65) it is $11.02. Source: USPS Notice 123, Price List. Sent online through Piloxa, a first letter is $9.95 all in; after that a one-page letter is $12.97, or $15.97 with the electronic return receipt, printing and envelope included. Every fee, side by side, or work out a letter of any length with the Certified Mail cost calculator.

Electronic Return Receipt

A return receipt sent by email: a PDF showing the delivery date, the name and signature of whoever accepted the letter, and the delivery address. It is the same USPS return receipt service as the green card, delivered electronically, and it costs less. How the Electronic Return Receipt works.

Paper return receipt (the green card)

PS Form 3811, a green card attached to the envelope, signed at delivery and mailed back to the sender. Use it when a statute, court rule or contract names the card itself; otherwise the electronic version gives the same information. Electronic return receipt vs the green card.

Restricted Delivery

An extra service that limits delivery to the addressee or the addressee’s authorized agent; the addressee must be an individual named on the piece, not a company or a job title. Source: DMM 503.3.2.2. Restricted Delivery, explained.

Delivery time

Certified Mail travels at the speed of the class it is added to. For First-Class Mail the USPS standard is 1 to 5 days, and there is no delivery guarantee. If nobody is there to sign, “delivered” can come days or weeks after the first attempt. How long Certified Mail takes, and what is possible the same day.

Who signs for it

Certified Mail is delivered against a signature. Without Restricted Delivery, USPS can deliver it to the addressee, an employee, a competent member of the addressee’s family, or anyone authorized to represent the addressee. Source: DMM 508.1.4.1. Who can sign for Certified Mail.

PO Boxes

Certified Mail can be sent to a PO Box. The box gets a notice, and the box holder signs for the letter at the counter. If nobody collects it, it is returned as unclaimed. Certified Mail to a PO Box.

Refused

The recipient can refuse a certified letter when it is offered; it is then returned to the sender marked refused, and the tracking records the refusal. Once accepted and signed for, it cannot be refused afterwards. Whether a refusal counts as notice depends on the rule you are following. Source: DMM 508.1.1. Certified Mail refused by the recipient.

Unclaimed

When nobody signs, the carrier leaves a notice and the Post Office holds the letter for 15 days, or fewer if the sender specified fewer on the piece, then returns it marked unclaimed. Unclaimed is not refused: nobody turned it away. Source: DMM 508.1.1.7. Certified Mail unclaimed.

Returned to sender

A certified letter comes back because it was refused, unclaimed, undeliverable as addressed, or the addressee moved. The marking on the envelope and the tracking history say which; keep the returned envelope sealed. Certified Mail returned to sender.

Tracking

The tracking number is the article number on the receipt and the label, and it can be checked at usps.com. Gaps between scans are normal; a missing scan is not proof the letter was not delivered. Certified Mail tracking not updating.

Certificate of Mailing

A different, cheaper USPS service (PS Form 3817): a stamped slip showing a piece was presented for mailing on a date. It gives no tracking and no record of delivery. Source: DMM 503, Extra Services. Proof of mailing and the Certificate of Mailing.

Certified Mail vs Registered Mail

Certified Mail proves mailing and delivery. Registered Mail is USPS’s most secure service: the piece moves under a chain of receipts from acceptance to delivery and can be insured for its declared value. It is slower and costs several times more; for a notice or a demand, Certified Mail is the usual choice. Certified Mail vs Registered Mail.

Certified Mail vs Priority Mail and First-Class Mail

First-Class Mail and Priority Mail are mail classes that decide speed and postage; Certified Mail is an extra service added to either. Signature Confirmation is a separate service for Priority Mail and packages, not for First-Class letters. Certified Mail vs Priority Mail, First-Class and Signature Confirmation.

Certified Mail and the alternatives, side by side

No USPS service records what is inside the envelope. That record has to come from the sender: how to close that gap.

Sending it

• Send Certified Mail online — the whole process, start to finish, with the costs.
• Send Certified Mail without going to the Post Office — the three ways to do it from home.
• Send a PDF by Certified Mail — a finished document, printed exactly as it is.
• Filling in Form 3800 and addressing the envelope — if you mail it yourself.
• How to format a certified letter — with a sample and a notice template.
• Online certified mail services compared — eight services, named, with their prices and catches.

Proof and evidence

This is where most people are surprised. Certified Mail records that an envelope was mailed and delivered. It does not record what was inside it, and the receipt is only as useful as your ability to show which letter it belongs to.

• Proving what was in the envelope — the gap Certified Mail leaves, and how to close it.
• Does Certified Mail prove delivery? — what tracking and a return receipt establish.
• Proof of mailing and the Certificate of Mailing — the cheaper USPS option, and its limits.
• Certified Mail and proof of service — notice is not always service.
• Using Certified Mail records in court — what to bring, and what a judge looks for.
• A sample mailing record — every piece of evidence Piloxa keeps, filled in.

If you received a certified letter

Most searches about Certified Mail come from the other end: a notice slip in the mailbox and a letter waiting at the Post Office. Who sent me certified mail? covers how to find out and who usually sends it, how to pick it up covers the slip, the 15-day hold and redelivery, and how to respond to a certified letter covers the written answer, with the two most common cases on their own pages: a letter from a debt collector and a letter from an attorney.

Letters people send certified

Most Certified Mail is a letter that starts a clock or settles an argument: a demand, a dispute, a notice. Legal notices by Certified Mail covers when Certified Mail is the right method and when a rule asks for something else, and links every letter guide: demand letters, cease and desist, debt validation, security deposits, landlord notices, lease terminations, rent demands and HOA notices.

Have your AI prepare it

If you already drafted the letter in ChatGPT, Claude, Gemini, Grok or another assistant, it can hand the finished letter to Piloxa and prepare it for USPS Certified Mail. Ask it in plain words, for example: Send this letter by Certified Mail with return receipt.

The connector address is https://www.piloxa.com.e2b4.com/mcp (remote MCP, no key and no account to connect), and software that reads OpenAPI can use https://www.piloxa.com.e2b4.com/openapi.json. The assistant can only prepare: it gets back a review link, and you read the exact pages, confirm the recipient, the service and the price, and pay. Nothing is printed, mailed or charged before that. What an assistant can and cannot do with Piloxa.

Questions people ask

What is Certified Mail used for?

For letters the sender may need to prove later: demands, disputes, notices to end a lease, debt validation requests, notices required by a contract or a statute. It gives a dated mailing receipt and a USPS delivery record.

Does Certified Mail need a signature?

Yes. Someone at the address signs when it is delivered; if nobody is there, a notice is left and the letter waits at the Post Office. Without Restricted Delivery, that someone does not have to be the named addressee.

Is Certified Mail the same as Registered Mail?

No. Certified Mail records mailing and delivery. Registered Mail moves under a guarded chain of custody, can be insured for its declared value, and is slower and dearer. Most letters that need proof go Certified.

Can I send Certified Mail online?

Yes. Print-and-mail services print the letter, envelope it and hand it to USPS as Certified Mail. Piloxa does that from a pasted letter, a PDF or an AI assistant, and you approve the exact pages and the total before anything is printed.

Sources

• USPS Domestic Mail Manual 503: Extra Services
• USPS Domestic Mail Manual 508: Recipient Services
• USPS Notice 123: Price List

Postal rules checked against the USPS Domestic Mail Manual in October 2026. Legal rules differ by state and by situation.

Start here

• Send a certified letter online
• Certified Mail cost in 2026
• Proof of contents
• Legal notices by Certified Mail
• The longer guide: Certified Mail with proof