How to compare two PDFs
- Drop the original version into the left box and the revised version into the right box.
- Click Compare documents.
- Review the per-page summary: identical pages are skipped, changed pages list added lines (green) and removed lines (red).
- Download the report as Markdown if you need to share or archive it.
Good to know
- Comparison is text-level: wording, numbers and clauses are diffed line by line.
- Pages that exist in only one of the two documents are flagged as added or removed.
- Scanned documents have no text layer — OCR them first (see the OCR tool) if you need to compare scans.
- Typical use: contract redlines, thesis drafts, invoice revisions, terms of service updates.
Frequently asked questions
Does it compare images and layout?
No. This tool compares the text content of both documents. Visual comparison (pixel-level) is a much heavier operation and is deliberately not offered here.
What if the page count differs?
Pages are matched by number. If the revised document has extra pages, they are reported as "only in B"; missing pages as "only in A".
How exact is the text extraction?
It uses pdf.js, the same engine as Firefox's PDF viewer. Text with complex encodings or unusual fonts may extract imperfectly — worth knowing for scanned or heavily designed documents.