Add Page Numbers to a PDF

How to Add Page Numbers to a PDF

1. Select a PDF.
2. Choose header or footer position and a number format.
3. Set a starting number, and optionally skip the first page.
4. Export the numbered PDF.

What this tool changes

• Adds a page-number text object to the header or footer of the selected pages.

What it preserves

• All existing page content.

Good to know

• Numbering restarts or skips only where you explicitly configure it to.
• Numbers are drawn in Helvetica, which is referenced by name rather than embedded, so letter shapes come from the reader’s viewer while position stays fixed.

Number last, after the page set is final

Numbering should be the last structural step. Add numbers and then delete a page from the middle, and the sequence skips — 1, 2, 5, 6 — which looks worse than no numbering at all, because it reads as pages having gone missing rather than having been removed on purpose.

The order that works is assemble, order, remove what is surplus, then number. On a bundle drawn from several sources, that means you combine the files first, so a single continuous sequence runs across the whole document rather than restarting at each part, and settle the page order before numbering, because a number is only right if the page beneath it is.

If you renumber after a change, remember the old numbers are still on the pages: this adds a new sequence rather than editing an existing one.

Numbers already printed on the page

Most documents that need numbering already carry some. An extract of pages 14 to 16 still says 14, 15, 16 at the foot of its sheets; a report says "Page 7 of 40" even after you removed four pages.

A new sequence laid on top does not remove the old one, so the two will sit on the same page. That is fine if they are in different positions and the intent is clear — a bundle number in one corner and the source document's own numbering in another is normal in legal and tender work.

It is confusing if they overlap or conflict. Check where the existing numbers sit before choosing a position, and put yours somewhere the original does not use.

Choosing a position and a format

Bottom centre is the safe default for documents meant to be read as a sequence. Bottom outer corner suits anything that will be printed double-sided and bound, because the number stays visible at the open edge.

Keep clear of the printer's unprintable margin — typically 3 to 6 mm, more at the bottom on many inkjets. A number placed too close to the edge is a number that survives on screen and disappears on paper.

For formal submissions the format is often prescribed rather than chosen: continuous numbering across the whole bundle, a particular position, sometimes a prefix. Read the requirements before you start, because renumbering a completed bundle is the kind of rework that happens at the worst possible moment. Preparing a PDF bundle for submission covers that sequence.

What numbering costs, and what it leaves alone

Numbering every page of a three-page scan of just under four megabytes cost 1,002 bytes in our measurement — roughly 334 bytes a page. That is small enough to be irrelevant to any file you are likely to number, and the reason is worth knowing.

The font does not go into the document. The output names Helvetica and carries no embedded font program at all. Helvetica is one of the fourteen fonts every PDF viewer is required to supply, so the numbers always render — but the exact letter shapes come from whatever the reader’s viewer substitutes, usually Arial on Windows. Their spacing never changes, because the character widths are written into the file.

Position follows the page as you see it. A number set to the footer stays in the footer of the preview at every quarter turn, and it is drawn upright with the page rather than lying on its side with the sheet underneath. On a turned page that was not always so — a footer-centre number could end up halfway down an edge, sideways.

The more useful property is what numbering does not disturb. It draws onto the pages already in the document rather than building a new one, so the document properties survive: we measured title, author, subject, and creator all coming back unchanged. Reordering, removing, or extracting pages wipes those same fields, because those operations rebuild the file. If a document needs to keep the details it arrived with, numbering is safe; reordering it is not.