PDF Page Number

Starting number and physical position

The number printed on a page and the page's position in the file are different things, and almost every real numbering job depends on the difference. A report with a cover and a contents page usually needs numbering to start at 1 on the third physical page. That means setting both where numbering begins and what value it begins with, which are two separate settings people frequently conflate.

Position and margins

Bottom centre is the safe default and works for both single-sided and double-sided output. Bottom outer corner, alternating left and right on facing pages, is the convention for bound documents so the number is always visible on the outer edge when flipping. Whatever you choose, keep the number inside the printable margin: most printers cannot print within about 5 millimetres of the paper edge, and a number placed too low is silently clipped.

Watch for collisions

Numbers are drawn on top of existing content. If the source document already has footers, the new number can land on top of them. Check a page from the middle of the document rather than only the first page, since front matter often has a different layout from the body.

Formats

Plain numerals suit most documents. "Page X of Y" is useful for anything that might be printed and separated, because a loose page identifies both its position and whether any pages are missing. Roman numerals for front matter followed by arabic for the body is the standard scholarly convention and needs two passes with different settings.

Numbering is permanent once saved

Unlike a word processor, a PDF has no concept of a live field that recalculates. The numbers become static page content, so inserting a page afterwards leaves every subsequent number wrong. Number last, after the document's page order is final.