How to compare two PDFs
- Drop the original PDF on the left box and the changed version on the right.
- Press Compare. The text of both documents is extracted and compared line by line.
- Removed lines are marked − in red and added lines + in green, each with its page number. Untick Show changes only to see the full text with changes in context.
When to compare PDF versions
Contracts, leases, terms and conditions, policies and specifications often come back "with a few small edits". Comparing the old and new PDFs shows exactly what changed, so a reworded clause, a different date or a new fee cannot slip through unnoticed. It is also useful for checking proofs against the approved copy and for spotting changes between two releases of a manual.
The comparison looks at text, not layout: changes in fonts, images or spacing are not reported, and a paragraph that reflows onto different lines may show as changed. Ticking Ignore spacing differences reduces this noise. Scanned PDFs have no text layer, so run them through OCR first.
Both files are read in your browser with PDF.js. Nothing is uploaded, which matters for confidential legal and business documents.
Can it compare scanned PDFs?
Not directly. Convert them to searchable PDFs with the OCR tool, then compare the results.
Does it show formatting changes?
No. Only the words are compared. Bold, colours, images and layout changes are not detected.
Is there a size limit?
Documents of a few hundred pages compare comfortably. Extremely different documents fall back to a simpler comparison.