Why add page numbers?

Page numbers in a PDF help readers navigate, reference specific content, and ensure pages stay in order if printed and dropped. They’re standard in: books, theses, reports, contracts, legal documents, scanned multi-page documents, meeting minutes, and academic papers. While professional documents created in Word or LaTeX include page numbers automatically, PDFs from scans, screenshots, or some online sources often lack them. Adding page numbers after the fact is essential for: legal filings (every page must be numbered), academic submissions, distributed reports where readers reference specific pages, and any document over 5 pages. This tool inserts page numbers in your chosen position and format using pdf-lib, browser-side and private.

How to use this tool

1. Upload your PDF — Tool reads the page count to display.
2. Choose position — 6 positions: top/bottom + left/right/center. ‘Bottom center’ is most common (default).
3. Choose format — ‘1, 2, 3’ (simple sequential), ‘Page 1 of N’ (shows total), ‘- 1 -‘ (centered with dashes, book style).
4. Set starting number — Default 1, but you can start at any number. Useful if the document is part of a larger compilation.
5. Click ‘Add page numbers’ — Numbered PDF downloads automatically. Original is unchanged.

How page numbers are added

The tool uses pdf-lib’s drawText() method to overlay page numbers on each page:

1. Load PDF with pdf-lib
2. Embed a standard font (Helvetica)
3. For each page: calculate position based on choice (top/bottom + left/center/right)
4. Draw the number text at calculated position with size 10pt
5. Save and download the modified PDF

Position offsets:

• Bottom: y = 20 pixels from bottom edge
• Top: y = 30 pixels below top edge
• Left: x = 30 pixels from left edge
• Right: x = (page width – text width – 30) pixels from left
• Center: x = (page width – text width) / 2

Text color is medium gray (RGB 0.3, 0.3, 0.3) – visible but not distracting. Size 10pt is standard footer/header text size.

Examples

• 50-page report: Bottom center, ‘Page X of N’ format → ‘Page 1 of 50’, ‘Page 2 of 50’, …
• Scanned legal contract: Bottom right, ‘1, 2, 3’ format – legal filing standard
• Academic thesis: Bottom center, sequential numbers, starting after the title page (set start = 1 but include cover page)
• Book draft: Bottom center, ‘- 1 -‘ format with dashes for traditional book look
• Chapter 2 of a series: Set starting page = 25 (if chapter 1 ended at page 24)

Tips & best practices

• Bottom center is standard for most documents – readers expect page numbers there
• Top right is common for academic papers (headers often have title at top left)
• Avoid bottom right with auto-incrementing – one-sided printing always shows on right; double-sided printing puts even pages on left side
• ‘Page X of N’ format helps readers know how much is left – good for long documents
• Use ‘sequential numbers’ for documents that may have inserts or be partially distributed
• If your document already has page numbers from the source software, don’t add more – check first
• For mixed orientation documents, the page number position adjusts to the page’s actual orientation

Limitations & notes

The tool adds page numbers in a single style/position across all pages – you can’t have different positions for different pages in one pass. Page number text color is fixed at gray; can’t customize. Font is Helvetica only – no other font choices. For complex page numbering (Roman numerals for front matter, Arabic for main content), would need separate passes for different page ranges. Doesn’t support custom prefixes or suffixes like ‘Section 1.X’.

Frequently Asked Questions

What if my PDF already has page numbers?

The tool will add new ones on top – you’ll have two sets of page numbers. To avoid this, either don’t run this tool, or use a more advanced editor to remove existing numbers first.

Can I start at a number other than 1?

Yes – use the ‘Start at’ field. Common cases: continuing a previous document, skipping a cover/title page, or matching the document’s logical page count.

Will the page numbers be searchable?

Yes – the numbers are added as actual text, not as images. They’re selectable, copyable, and searchable in any PDF viewer.

Can I choose where on the page?

Yes – 6 position options: top/bottom + left/center/right. Most documents use bottom-center or bottom-right. Academic papers often use top-right.

Will adding page numbers change the existing content?

No – the tool only overlays new text. Original content is unchanged. The output is essentially the original PDF with page number text added on top of each page.

Can I use different colors or fonts?

Not in this tool – color is fixed at gray, font is Helvetica. For custom styling, use a desktop tool like Adobe Acrobat or a PDF editor. Most documents look clean with gray Helvetica 10pt, which is what we use.

What if my pages have different sizes?

Page numbers adapt – the tool calculates position relative to each page’s dimensions. Mixed Letter/A4 documents work fine, as do mixed portrait/landscape.

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