How to Add Page Numbers to a PDF (Free, on Windows)

Adding page numbers to a PDF is the finishing pass on anything that will be printed, bound, cited or discussed on a call. It is also the step that goes wrong most often, because page numbers in a PDF are not what people assume they are.

The short answer

1. Open PDF Tools from the BizTray tray.
2. Add the PDF — or a whole folder.
3. Choose position, format, starting page and starting number.
4. Apply and save.

No engine download, nothing uploaded, no watermark on the output.

The thing to understand first

PDF page numbers are not dynamic. They are drawn onto the pages as ordinary content, exactly like a watermark. They do not recalculate.

That single fact drives every piece of practical advice here:

• Add a page in the middle afterwards and the numbers skip. There is no field to refresh.
• Delete a page and the sequence jumps.
• Reorder pages and the numbers travel with their pages, so the document reads 1, 2, 7, 3.

So the rule is simple: number last. Merge, split, delete, reorder and rotate until the document is final, and only then number it. Doing it in the other order is the single most common reason people end up numbering the same document twice.

Where to put them

Convention exists for good reasons here:

• Bottom centre — safest default. Works for single- and double-sided printing, never collides with binding.
• Bottom outer corner — the book convention, alternating left and right on facing pages. Looks considered for anything properly bound.
• Top outer corner — fine for reports, easier to thumb through.

Two things to avoid: the binding edge, where a hole punch or comb binding will eat the number, and the extreme page edge, where a printer's non-printable margin will clip it. Keep roughly 15 mm of clearance.

Front matter and the starting number

The other common requirement is that numbering should not start at the physical first page. A cover and a contents page usually stay unnumbered, with the body starting at 1.

That needs two separate settings, and mixing them up is easy:

• Which page numbering starts on — page 3, say.
• What number it starts at — 1, so page 3 shows "1".

Set the first without the second and page 3 shows "3". Both are common requirements and they are not the same control.

If the document is a submission with a numbering requirement — a thesis, a tender, a court bundle — read the spec before numbering rather than after. Bundle numbering in particular often has to be continuous across several merged documents, which means merging first is not optional.

Numbering after a merge

This is the workflow that produces most of the demand for this feature. You merge five reports into one bundle, and the result has five independent numbering schemes printed on it, all starting at 1.

The fix is to number the combined document. The original numbers are already drawn onto their pages and cannot be removed by numbering over them — so if the sources carry visible numbers, position the new sequence somewhere that does not collide, usually the opposite corner or the top.

Doing it on your own machine

PDF Tools numbers pages alongside watermarking, flattening, metadata cleaning and adding or removing passwords — no page cap, no size ceiling, nothing uploaded. A 900-page bundle numbers in one pass, and a whole folder can take the same settings in one batch.

Practical notes:

• Preview one page before a long run. Position and size that look right on screen can sit badly on the printed page.
• Match the document's type size. Page numbers set at 14pt on a 10pt document look like an error.
• Number after flattening, not before, if you are also flattening forms.

A note on why this is free

BizTray shares a portion of your spare internet bandwidth through a vetted partner rather than charging you. It relays other parties' web traffic and never touches your documents. Sharing is switchable off from Settings or the tray, and the tools do not run while it is off. See How it's funded.

Related

• How to merge PDF files — do this first.
• How to add a watermark to a PDF — the other finishing pass.
• How to reorder PDF pages — also before numbering.