How the numbering counts, and what it does to the page

Page numbers follows each page's position in the file. The first page you number shows the Start numbering from value, and every page after it is counted from there, whether it gets a number or not. That explains most of the results people don't expect.

Skipped pages keep their place in the count

Say a 30-page report has a fold-out map on pages 6 and 7 that shouldn't carry a number. If you type 1-5, 8-last in Apply only to pages, page 8 of the file still gets the number 8, so the printed numbers match the page numbers your PDF reader shows. The same goes for odd on its own: pages 1, 3 and 5 of the file are numbered 1, 3 and 5, and the even pages stay blank.

The count starts at the first page you number, not at page 1 of the file. With 3-last and Start numbering from left at 1, page 3 of the file is numbered 1 and page 4 is numbered 2, which is how you leave a cover and a contents page out of the numbering.

{total} is the number the last page of the file would get under the same count, whether that page is numbered or not. With 3-last on a 30-page file that's 28, so the last page reads "Page 28 of 28". With odd on a 30-page file it's 30, so page 29 reads "Page 29 of 30", and with 1-5, 8-last the skipped fold-out pages still count, so every number reads "of 30".

Roman numerals for the front matter

Books and theses often number the preface in lowercase Roman numerals and restart at 1 for chapter one. Two passes handle that. Number the front pages (say 2-6) with Numbers set to i, ii, iii, then run the result again on 7-last with digits, starting from 1. In that second pass, Page {n} of {total} gives "Page 1 of 94" on the first chapter page, which is what readers expect.

{total} follows the same Numbers setting as {n}, so on a 12-page file numbered in Roman numerals, page 4 prints "Page iv of xii". Keep in mind that {total} counts to the last page of the whole document, so for front matter only, plain "{n}" usually reads better than "Page {n} of {total}". Roman numerals stop at 3999; above that the number is written in digits. Letters run from A to Z and then continue AA, AB, the way spreadsheet columns do.

What Increase margins actually does

Setting Document margins to Increase margins doesn't add paper. It shrinks everything on the page by the same factor and centers it, which leaves a clear band at the top or bottom. The band is the Distance from edge plus 1.4 times the font size. With the defaults (20 pt and 10 pt) that's 34 pt, so on a Letter page the content ends up at about 96% of its original size, and the side margins grow slightly too. Links, comments and form fields are moved with the content so they still line up.

It only touches pages that get a number. Leave the cover out and it stays full size while page 2 onwards is a little smaller, which you may notice in a printed booklet. If a page would have to shrink below 30% of its height, which only happens with a huge font or distance, it's left alone.

The rest of the file stays as it was

The tool opens your PDF, adds one line of text to each chosen page and saves it. Bookmarks, links, form fields and the document's title and author are kept. The exception is a password: a protected file is unlocked when you open it and saved without one, so finish with Protect PDF if it needs protecting again.

If your text contains characters the chosen font doesn't have, such as a Greek file name with a font that only covers Latin letters, the tool switches to a fallback font that covers more of them instead of quietly dropping letters.