Add Page Numbers to a PDF

How do you add page numbers to a PDF?

Adding page numbers to a PDF means stamping a number onto every page — or every page after a cover — in a chosen corner or edge, in a chosen format, without touching anything else on the page. Word processors do this automatically when they export, but a PDF you received, scanned, or merged from several sources usually has none, and there's no built-in way to add them after the fact without paying for software.

This tool does the whole job in the browser tab it's open in. Drop a PDF onto the page or click to choose one, pick a position and a format, set where the numbering should start and which page it should start on, and download the result. The output keeps everything from the original — text stays selectable, images are untouched — with only the number added on top.

How to add page numbers to a PDF

1. Drop in your PDF. Nothing is uploaded — the file is opened and rewritten right in this browser tab.
2. Choose position, format, and start. Pick one of six positions, one of six number formats, the starting number, which page numbering should begin on, plus font size and margin if you want to adjust them.
3. Download the numbered PDF. The download button gives you the finished file, along with the page count, how many pages were numbered, and the resulting file size.

Rotated pages, and why numbers end up sideways

A PDF page can carry a rotation flag that tells the reader to display it turned 90, 180, or 270 degrees, while the actual content underneath is stored unrotated. A page scanned sideways is a common example: the reader shows it upright, but its raw content box might be 400 units wide by 600 tall even though what you see on screen is 600 by 400.

A tool that ignores this and draws at, say, bottom centre using the page's raw coordinates ends up placing the number up the side of the page, lying on its side, because it never checked how the reader is actually rotating that content into view. This tool computes the position in the space the reader displays, maps it back into the page's own coordinates, and rotates the number by the same angle so it always reads upright, exactly where you asked for it. That mapping was tested against an independent transform over 1,700 points across all four possible rotations, with the corners checked by hand as well — a round-trip check on its own can pass for a mapping that's simply self-consistent and still wrong, so it wasn't relied on alone.

The other detail that trips up simpler tools is the CropBox. A PDF reader displays a page's CropBox, not its MediaBox, and while the two are usually the same, a trimmed document can have a CropBox smaller than the underlying MediaBox. Measuring a margin from the MediaBox on a file like that places the number outside the area anyone actually sees. Margins here are measured from the CropBox, so they match what the page looks like on screen.

Honest limits

Numbers are drawn using Helvetica, one of the fourteen standard fonts every PDF reader already includes, so no font file gets embedded in your download. On a 100-page document, that adds roughly 175 bytes per page — the number itself, not a font program.

The tradeoff is encoding. Those standard fonts use WinAnsi encoding, which covers Latin text fine, including accented characters — “Página 1 de 10” and “Page 1 sur 10” both work — but cannot represent Arabic script at all. Embedding a font that could would mean shipping a font file with every single output, which is exactly the weight avoided by using a standard font in the first place. So the worded formats are offered in Latin-script languages, and the Arabic version of this page offers only the formats built from digits and punctuation. The tool checks every label before drawing anything, so an unencodable format is refused up front rather than producing a file that's numbered on some pages and not others.

Nothing about the existing page content is re-rendered or re-compressed. The number is drawn on top of what's already there — the original text stays selectable, and any images stay exactly as they were. A page that arrived rotated leaves rotated, which was verified by reloading the output and reading the flag back.

Why is it free?

The entire process — reading the PDF, computing positions, drawing the numbers, saving the result — runs in your browser. Nothing is uploaded to a server, so there's no bandwidth or processing cost tied to how big or how many files you number. That's also why there's no account to create and no watermark added to the output.