Compare two PDFs
Add the old and new versions, and see every word that was added or removed, highlighted side by side.
Drop Original
The earlier version
Drop Revised
The newer version
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What it does
Compare PDF, explained
To compare two PDFs, load the original and the revised version; the tool extracts the text from both, lines them up, and highlights words that were added (in the new file) and removed (from the old one), with a list of changes you can click through. PDFBetter runs the comparison in your browser, so neither file is uploaded.
Read more
This answers the question “what did they change?” — a contract sent back by the other side, a policy revised by HR, a vendor's updated price sheet, a new edition of a form. Reading both versions side by side by eye misses a changed “may” to “shall”; a text comparison does not.
Know what it ignores. The comparison works on text, so changes in formatting (bold, font, color), images, logos, signatures and drawings are not reported. Moving a paragraph shows up as a deletion in one place and an addition in another. Scanned documents have no text to compare until they are OCR'd.
Use the side-by-side view to eyeball layout changes the text comparison cannot see, and treat the change list as a guide, not a legal redline certification.
How to do it
Compare two PDFs in 4 steps
1Two versions
2Compare them
3Changes marked
- 1
Add both versions
Drop the original on the left and the revised file on the right. Both are read in your browser.
- 2
Run the comparison
Text is extracted and aligned; additions and deletions are highlighted on each side.
- 3
Review the changes
Click through the change list; both views scroll to the same spot.
- 4
Check what text can't show
Scan the side-by-side pages for image, signature or layout changes.
Example
Before and after
Version 1 and version 2 of a 7-page NDA; the counterparty said they “only fixed typos”.
Nine highlighted differences: two typo fixes, the confidentiality term changed from 2 years to 5 years, and “exclusive jurisdiction” changed from New York to Delaware.
Settings & formats
What you can control
- Side-by-side view
- Original and revised pages next to each other, scrolling together.
- Change list
- Each insertion and deletion with its page, for quick review.
Input
Output
Good to know before you start
- Only text is compared. Changes to images, signatures, logos, colors, fonts and layout are not detected.
- Scanned PDFs must be run through OCR first, and OCR errors can show up as false differences.
- Moved paragraphs appear as a deletion and an addition rather than a move.
- Headers, footers and page numbers that changed with repagination may appear as differences.
If something goes wrong
If something goes wrong
- Every line shows as changed.
- One file is likely a scan or uses a different text encoding. Run OCR on the scanned version and compare again.
- The tool says a file has no text.
- That file is image-only. Run OCR PDF on it first.
Compare PDF: questions people ask
Are my files uploaded?
No. Both files are read and compared in your browser.
Does it detect formatting changes like bold or font size?
No. The comparison is text-only; formatting, image and layout changes are not reported.
Can I compare a Word file with a PDF?
Convert the Word file with Word to PDF first, then compare the two PDFs.
Can I compare scanned documents?
Run OCR PDF on each scan first. OCR mistakes may appear as small false differences, so review them.
Is this a legal redline?
It is a review aid that highlights textual differences; it does not certify that nothing else changed. PDFBetter is not a law firm.
Do I need an account?
No. Comparison is free without an account.