PDF page numbers and Bates numbering explained

Adding page numbers to a PDF sounds like a one-line job, and it is, until the document has a cover page, an appendix, or three sections merged from separate files. Then the questions start: does the cover count as page one, should the first numbered page show as 1 or as 3?

There is also a second kind of numbering that most people meet only when a lawyer is involved. Bates numbering and ordinary page numbering look similar on the page and behave quite differently. Here is both, including the details that cause the most rework.

Page numbers and pagination are different things

A PDF has a page tree, which is the internal ordered list of pages. That order is the pagination, and it is what a viewer follows when you scroll or print. Page numbers added by a tool are a visual stamp drawn onto the page content, in the same layer as any other text. The consequences follow directly:

• Adding numbers does not change pagination. A stamped "17" does not move the page, and it does not make the document 17 pages long.
• Reordering pages later does not renumber anything. Stamp a document, then delete a page in the middle, and you have one that counts 1, 2, 4, 5. Burned-in numbers are just text and cannot update themselves.
• Stamps are removable, but only as content. Editing the page content stream to delete them is possible. There is no switch labelled "remove page numbers", because the PDF does not know those characters were a number.
• A separate mechanism exists for display. PDF page labels let a viewer show a different label from the physical page index, so page 4 of the file can display as "ii". Most viewers honour labels in the navigation box and none of them render the label visibly on the page.

That is why sequence matters: reorder, delete, split, merge and rotate first, then add numbering last. Doing it the other way round means doing it twice.

How to set page numbers up properly

1. Decide whether the cover is page one. The most common convention is to count every physical page but suppress the stamp on the cover, which keeps the printed number matching the page's real position in the file. That matters as soon as anyone refers to "page 12" in a printed copy.
2. Choose the position and mirror it. Outside edge for duplex printing, centred for single-sided, bottom-right for most business documents. Mirrored outside edges stamp odd pages on the right and even pages on the left.
3. Set a first numbered page. If the cover is unnumbered, decide whether the second page reads "1" or "2". Neither is wrong, but mixing them across a document is.
4. Choose a format. Plain numerals such as 7, or a fuller form such as Page 7 of 42. Roman numerals are the convention for front matter in longer documents, with arabic numerals restarting at 1 for the body.
5. Set size and margin. Around 9 to 10 points is legible without competing with the content. Keep the stamp at least 36 points from every page edge, or printers may crop it, and never place a number where a footer already has text.
6. Use a page range for a second scheme. Front matter in roman numerals and the body in arabic means two passes over two ranges. Check the join between them.

Bates numbering, and why legal teams need it

Bates numbering is a convention from paper document production, where each page of a disclosure set was stamped with a sequential identifier so any page could be cited unambiguously. Digitally it works the same way: a fixed prefix plus a zero-padded sequential number, for example ABC-000123, running continuously across the whole production set rather than restarting for each document. The distinguishing features matter practically:

• One continuous sequence. If a set contains forty documents, numbering runs from the first page of the first to the last page of the fortieth without restarting, which is what makes a citation unambiguous.
• Fixed width. Zero padding to six or seven digits keeps stamps the same length, so they stay aligned when printed and sort correctly as text.
• A configured starting number. A new production usually begins at a chosen value, and supplements continue from where the earlier set ended.
• Applied to every page. Covers, index pages and blank separator sheets are stamped too. Consistency is the entire point: a set where three pages are unnumbered is a set where those pages cannot be cited.

Because the stamp is a page-content operation, the same caution applies. Produce the final set first, stamp it, then stop editing. If a document is added afterwards, either append it with the next numbers in sequence or restamp the whole set. Partial restamping produces duplicate numbers, which defeats the purpose of the exercise.

Common mistakes and how to avoid them

• Numbering before assembling. Merging three numbered PDFs gives you three sequences that each start at 1. Assemble, then number.
• Forgetting the page-range boundary. When numbering pages 3 to 20, confirm whether the tool counts from the start of the document or the start of the range. The difference is a whole sequence shifted by two.
• Stamping over existing content. A footer with a reference number, a confidentiality notice or a watermark is easy to stamp on top of.
• Using a font that is not embedded. If the tool relies on a font the viewer may not have, numbers can render inconsistently or disappear.
• Restamping an already stamped document. Running the tool twice gives you two numbers on every page, so check the pages before you start.

If the document needs a visible identifier that is not a sequence, such as a draft notice or a client name on every page, that is watermarking rather than numbering. Either way the workflow is the same: finish the document, stamp it once, and keep an unnumbered copy as the master.