LetterAgent
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Certified mail has no page limit, but weight does the limiting for you: anything over one ounce costs more, and around 13 ounces the letter crosses into parcel pricing. So the real question is weight, not pages. A certified letter can hold as many pages as you can fit in the envelope while the item stays a mailable letter.
| Weight | What happens |
|---|---|
| Up to 1 ounce | Standard letter postage plus the certified fee. A typical 4-to-6 page letter with a normal envelope fits here. |
| Over 1 ounce | Additional ounce postage applies for each extra ounce. Still a letter, just a heavier one. |
| Over 3.5 ounces | No longer letter-rate eligible: it prices as a large envelope, at a higher per-piece and per-ounce cost. |
| Over 13 ounces | The practical ceiling for letter-format mail: above this the item moves to parcel pricing with parcel rules. |
Thirteen ounces is where the postal service stops treating your item like a letter. Above that weight, you can't just drop it in a collection box with stamps on it: anything over 13 ounces bearing only stamps has to be presented at a retail counter, a rule the post office enforces for security reasons. The item also gets priced and handled under parcel rules rather than letter rules. So if you're asking "how many pages can I send certified," the useful reframe is "will it stay under 13 ounces?" For standard printer paper, that ceiling is generous: dozens of pages, more than most certified letters ever need.
Yes. Certified mail is a service added on top of First-Class mail, and it rides on letters, large envelopes, and small parcels alike. This surprises people who think of certified mail as one specific envelope. Sending a thick contract in a large envelope? Add certified service to it. The green card and the tracking attach to the item regardless of its shape. The catch is cost: certified plus large-envelope postage plus the extra ounces adds up, so weigh the item on a kitchen scale before you guess.
Certified Mail itself is a domestic US service and doesn't go to Canada, so the page-limit question doesn't arise for certified cross-border mail. The international equivalent for proof of delivery is registered mail, which has its own weight and dimension rules under the universal postal agreements. If you need high proof of mailing for a Canadian recipient from the US, registered mail is the lane, and the weight rules of international first-class mail apply instead.
LetterAgent's registered option (US Certified Mail / Canada Registered Mail) adds tracking and proof of delivery to your letter. Letters are 8.5x11 single-sided pages in a standard double-window envelope, so in practice very long letters still fit the certified envelope comfortably; the quote verifies your page count and the exact price is approved by you before anything goes out. Recipients need a US or Canadian address; certified-style proof for international recipients outside the US and Canada isn't available.
Ready to mail it? Send your letter with LetterAgent: describe it to your AI assistant, approve the exact quoted price, and it is printed and mailed.
LetterAgent is a working name. Prices include print, postage, and our service fee. US prices in USD, Canadian prices in CAD (Canadian prices exclude applicable sales tax, added at checkout). Currently in private testing.
Need help? Ask your assistant: it can check a job's status any time. If it ever can't handle something: hello@getletteragent.com