Add page numbers to PDF

Choose a PDF and page numbers are drawn onto every page as real text. You control where they sit, what they look like, which page numbering starts on, and what number that page gets — which are two separate settings, and the reason most numbering jobs go wrong.

The two numbers people confuse

"Start on page 3" and "start counting at 3" are different instructions, and nearly every complaint about page numbering comes from a tool that only offers one of them.

A thesis is the standard example: the cover and the acknowledgements should carry no number at all, and the introduction — physically the third sheet — has to be printed as page 1. That needs "start on page 3" together with "first number is 1".

The opposite case is just as common: a chapter extracted from a longer manual is physically page 1 of your file but must read as page 48 so it matches the rest of the binder. That is "start on page 1" with "first number is 48". Both are one form away from each other, so both are supported here.

Where to put them, and why it matters more than it looks

Bottom centre is the safe default and the convention for most printed documents. Bottom outer edge — right on odd sheets, left on even — is the book convention, and it exists because that is the corner a reader's thumb exposes when flipping. This tool places numbers at a fixed position on every page rather than alternating, which is correct for single-sided documents and for anything read on screen.

Two practical cautions. If the document will be bound or hole-punched, keep the number away from the binding edge or it disappears into the spine. And if the pages already have a footer, a number stamped at the same height lands on top of it — there is no way for a tool to know what is already down there, so check one page before running the whole file.

Why there is no "Page 3 of 12" in Chinese

The style options here are digits and Latin words: 3, or 3 / 12, or Page 3 of 12. There is deliberately no 第 3 頁 option, and the reason is worth understanding rather than being annoyed by.

PDF ships with fourteen standard fonts that every reader is required to have, and the numbers are drawn with one of them, Helvetica. That is what keeps the output small and guarantees it displays identically everywhere. Those fonts have no Chinese glyphs at all. Drawing 頁 with Helvetica does not produce a small mistake; it produces nothing, or a run of blanks.

The alternative is embedding a CJK font, and a usable Traditional Chinese font is several megabytes even when subsetted — which would be added to your document. That is a legitimate tool, but it is a different tool with a different size trade-off, so we would rather say this plainly than offer an option that silently outputs empty space.

What is actually written into the file

The numbers are real PDF text, not an image stamped over the page. You can select them, search for them, and they stay crisp at any zoom or print resolution. Everything already on the page is untouched — no existing content is re-encoded, so image quality and text fidelity are exactly as they were.

The numbers become part of the page content, which means they are not an annotation layer you can toggle off later. If you may need the original, keep an unnumbered copy. Rotation interacts with this too: numbers are drawn in the page coordinate system, so if you plan to rotate pages as well, rotate first and number afterwards.

Local, so there is no document to trust anyone with

Numbering is one of the last steps before a document goes to a supervisor, a client, a court or a printer — which means it happens when the file is complete and at its most sensitive. Uploading a finished thesis or a full contract to a stranger's server for something as mechanical as stamping numbers is a poor trade.

Here the whole operation runs in this browser tab: pdf-lib loads the document, embeds Helvetica, draws the text and saves the result to a Blob. Open the Network tab in developer tools while you do it — nothing carrying your document appears, and the Content-Security-Policy on this page means your browser would block it even if our code tried.