How to add page numbers to a PDF
- Choose your PDF with the box above, or drop the file onto it.
- Pick a Position and a Format: 1, 2, 3, Page 1, 1 of 10, Page 1 of 10, or roman numerals.
- Set the Start number (0 is allowed), the Font size (6 to 48 pt) and the Distance from the edge.
- To skip a cover or appendix, set First page to number and Last page to number. The line under the fields shows the first and last label.
- Select Add page numbers. The numbered copy downloads and your original stays untouched.
How the numbers are placed
The pdf-lib library draws each label in Helvetica on top of the page. A page's label is Start number + (page - First page to number). In the "of" formats the total is the last number in the run: Start number + pages numbered - 1. Distance is measured from the visible area (the crop box), and top labels are set so the digit tops sit that far from the edge. Pages stored with a 90, 180 or 270 degree rotation get turned text, so the number reads upright in the corner you chose (ISO 32000-1, section 7.7.3.3).
Worked example
Select Try a sample PDF (3 pages, US Letter, 612 x 792 points) and keep the defaults: Bottom center, 1, 2, 3, start 1, 12 pt, 0.5 in. The tool reports "Numbered 3 pages (pages 1 to 3). First label: "1"." A Helvetica digit 1 is 0.556 em wide, so the label is 0.556 x 12 = 6.67 points wide and is centered at x = (612 - 6.67) / 2 = 302.66 points, with its baseline 36 points (0.5 in) above the bottom edge. The download is sample-numbered.pdf.
Limits and edge cases
- Text only. You get Helvetica in dark gray, with no custom prefix or color.
- Existing numbers stay. If they sit in the same corner the two sets overlap, so choose another position.
- Password protected PDFs must be unlocked first with PDF Password Remover.
Join chapters first with PDF Merger, and fix sideways pages with PDF Page Rotator.
Frequently asked questions
How do I add page numbers to a PDF starting from page 2?
Set First page to number to 2 and Start number to 1. The cover page stays blank and page 2 gets the number 1. For page 2 to show the number 2, set Start number to 2 instead.
How do I add Page 1 of 10 to a PDF?
Choose Page 1 of 10 in Format. The total is the last number in the run, so a 10 page PDF numbered from 1 ends with Page 10 of 10. If you skip pages or start above 1, the total is the last number shown, not the page count of the file.
Can I use roman numerals for front matter?
Yes. Choose i, ii, iii or I, II, III in Format and set the page range to the front matter. Roman numerals run from 1 to 3999. To number the rest with ordinary digits, run the downloaded file again with the remaining pages.
Will the numbers sit in the right place on rotated or cropped pages?
Yes. The tool reads the rotation and the visible area (the crop box) of each page and places the number where you see the corner or center on screen, even for landscape scans stored as rotated pages.
Sources: ISO 32000-1 (PDF 1.7), pdf-lib documentation.