Add page numbers to a PDF.
Stamp clean page numbers onto every page — pick the position, the starting number and the format, without a single page leaving your device.
Three steps, no waiting on a server
Altto's page-numbering tool works right in your browser tab, so there's no upload queue and no “processing your file” spinner tied to someone else's servers.
Add your PDF
Drop in the PDF you want numbered.
Set position and format
Choose where the numbers go, what page to start counting from, and the format.
Save your PDF
Get back the same document with clean page numbers stamped onto every page.
Why this runs in your browser, not on a server
Even a simple task like numbering pages usually means handing a document to a stranger’s server first. Altto skips that step completely — there’s no server for it to go to.
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Nothing is uploaded, everEvery PDF is handled by code that runs in this browser tab, because there’s no server on the other end. That also means we can’t see it, copy it or keep it.
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No account, no email wallNumber as many PDFs as you like without signing up or handing over an email address.
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Only a small number is addedThe rest of each page — text, images, layout — is untouched.
documents stored on our servers. There’s no server involved at all — the numbered PDF is built once, then everything happens locally.
Frequently asked questions
The practical details on what this tool can and can’t do. Want to trim the margins too? See Crop PDF.