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Yes, but not in one pass unless your machine has a duplex feeder. A fax scans one side at a time, so with a regular feeder you flip the stack and run it through twice. Most all-in-ones send both passes as one job. The recipient gets the pages in the order you sent them, so keep the order straight.
It depends on the hardware:
| Machine type | How double-sided works |
|---|---|
| Duplex (two-sided) feeder | Scans both sides in one pass and sends them as one job; found on business-grade machines |
| Single-sided feeder | You load the stack, send side one, flip the whole stack, and run it again |
| Flatbed scanner only | You place each side on the glass one at a time; slow but works for a few pages |
| Online fax service | You upload a two-sided PDF and both sides go through automatically |
The non-obvious catch with the flip-and-resend method: page order. If you send sides 1, 3, 5 then flip and send 2, 4, 6, the recipient gets 1, 3, 5, 2, 4, 6. Some machines have a "2-sided" or "duplex" send setting that interleaves correctly, but many don't. The reliable manual method is to note the order before you dial and tell the recipient what to expect, or better, scan to PDF first, arrange the pages, and fax the file.
Contracts, insurance forms, and government paperwork often arrive double-sided, and people fax them without realizing the backs are blank-feeling but not blank. Before faxing, fan through the stack and check every back for content: signatures, initials boxes, and "continued on reverse" notes live there. A faxed contract missing its signature page is worse than useless, because the recipient assumes the file is complete. If the backs are genuinely blank, there's nothing to send. If they have content, each back is its own page in the transmission, and your page count doubles, which matters for per-page services.
No. A fax has no concept of front and back; it transmits a sequence of pages, and the recipient's machine prints them as a stack of single-sided sheets. If page 2 is the back of page 1, the recipient has to figure that out from context, which is why a cover page noting "2-sided original, pages in order" saves confusion. One more subtlety: many offices print received faxes single-sided by default, so a 4-page double-sided original becomes 8 sheets on their end. Nobody minds, but it's worth knowing when you wonder why the confirmation report says 8 pages for your 4 sheets of paper.
Scan first, then fax the file. A phone scan of both sides takes a minute, the PDF keeps the pages in the right order, and you skip the feeder entirely. That's also how LetterAgent handles it: describe the document to your AI assistant, upload the file, approve the exact quoted price, and the fax is sent to US and Canadian fax numbers with every side included. Fax is currently in testing, so check with your assistant about availability before you count on it.
Ready to fax it? Fax with LetterAgent: describe it to your AI assistant, approve the exact quoted price, and it is sent.
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.
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