Certified Mail
How to send Certified Mail and keep proof that survives a dispute
Certified Mail is cheap. Losing the proof afterwards is what costs people their case. This page covers what Certified Mail actually proves, what it costs in 2026, what to keep, and how to send one without leaving a conversation with your AI assistant.
What Certified Mail proves — and what it does not
USPS Certified Mail gives you a mailing receipt, a tracking number, and a record of delivery held by the Postal Service. Add Return Receipt and you also get the signature of whoever accepted it.
What it proves: that something was mailed to that address on that date, and that it was delivered or refused. What it does not prove: what was inside the envelope. Courts see this distinction constantly. The fix is boring and effective — keep the exact document you mailed, tied to the mailing record, so the contents are not a matter of memory.
What it costs in 2026
USPS prices effective July 12, 2026, for a one-ounce letter:
| Item | Cost |
|---|---|
| First-Class letter postage (1 oz, stamp) | $0.82 |
| Certified Mail fee | $5.55 |
| Electronic Return Receipt (emailed PDF signature) | $2.91 |
| Return Receipt green card (physical, mailed back) | $4.65 |
| Certified Mail with Electronic Return Receipt | $9.28 |
Metered or online postage is $0.78 instead of $0.82, so the same letter runs $9.24. The electronic return receipt costs less than the green card, arrives faster, and cannot be lost in a drawer.
Doing it yourself at the Post Office
- Print the document. Keep an identical copy — this is the copy that proves contents.
- Fill in PS Form 3800 (the Certified Mail label) and, for a signature, PS Form 3811 or request the electronic return receipt.
- Pay at the counter. Keep the stamped receipt: it is your proof of mailing date.
- Record the tracking number somewhere you will still have it in two years.
- Save the delivery scan and the signature when they arrive, with the copy of what you sent.
Steps 1, 4 and 5 are where evidence usually dies — a receipt in a coat pocket, a tracking number in a text message, a document that was edited after it was mailed.
What to keep, at minimum
- The exact file you mailed, unchanged, ideally with a checksum so you can show it was not edited afterwards.
- The recipient address as it was actually printed and mailed.
- The mailing date and the tracking number.
- Every tracking event through delivery, refusal or return.
- The signature record, if you paid for a return receipt.
Kept together, that set answers the only questions that matter later: what was sent, to whom, when, and what happened to it.
Sending one from ChatGPT, Claude or another assistant
Piloxa is an execution layer for exactly this job. Connect it as a custom connector at https://piloxa.com/mcp and you can say, in the conversation you are already in:
“Prepare this letter for Certified Mail with return receipt to the company in my case.”
The assistant cannot mail anything. It prepares the action and hands back a review link. You open it, attach the exact PDF, check the recipient and the price, authorize it, and only then does anything leave. Afterwards the document, its checksum, the address, the tracking events and the signature stay together as one record you can ask any assistant about later.
Status: Piloxa is opening in stages. Address checking, pricing, review and evidence work today; live mailing is switched on for invited accounts first. To be invited, write to support@piloxa.com.
Common questions
Does Certified Mail prove what was in the envelope?
No. It proves that a piece of mail was sent to an address and what happened to it. Proving contents is on you — keep the exact document, unaltered, linked to the mailing record.
Is Certified Mail the same as registered mail?
No. Registered Mail is a chain-of-custody service for valuables, is more expensive and slower. Certified Mail is the normal choice for legal notice.
What happens if the recipient refuses it or never picks it up?
The tracking record shows the attempt, the refusal or the return. For many legal notices, a documented refusal is as useful as a signature — the point is that the notice was properly sent.
Electronic Return Receipt or the green card?
Electronic costs $2.91 against $4.65, arrives as a PDF you cannot misplace, and is accepted for the same purposes. The green card is worth it only when someone specifically requires the physical card.
How long should I keep the proof?
Longer than you think. USPS tracking detail is not kept forever, and a dispute can surface years later. Save the records yourself rather than relying on being able to look them up again.