Compare PDF
See exactly which words changed between two versions of a document.
Got a new version of a contract, policy or report and need to know what changed? Add the original and the revised PDF, and ModifyPDF shows them side by side with removed words highlighted in red and added words in green.
How to compare two PDF files
- Choose the original PDF, then the changed version.
- Review the highlighted differences side by side, or click a change in the list to jump to it.
- Click “Download report” to save a PDF of the comparison.
Frequently asked questions
What kind of changes does it find?
Any change to the words: text that was added, deleted or reworded, including changed numbers, dates and names. Changes to images, colours or layout that don’t alter any words aren’t flagged.
Can I compare scanned PDFs?
Scans are pictures of text, so run OCR PDF on both files first, then compare the searchable versions.
Are my documents uploaded?
No. Both PDFs are read and compared inside your browser, which makes it safe for confidential contracts and drafts.
How do I compare two PDF files?
Add the original PDF, then the changed version. The pages appear side by side, with the original on the left and the new version on the right, and every difference highlighted.
What do the red and green highlights mean?
Red marks words that are only in the original. Green marks words that are only in the new version. A reworded phrase shows as red on one side and green on the other.
Can I skip the pages that didn’t change?
Yes. Tick “Show and report only pages with changes” to leave unchanged pages out, which helps with long documents.
Can I save or share the comparison?
Yes. “Download report” saves a PDF with both versions of each page next to each other and the same highlights. Neither original file is changed.
How the comparison works
The text of both PDFs is read in reading order. Lines are matched first, then every changed passage is compared word by word, so a single inserted word in a paragraph highlights just that word rather than the whole paragraph that reflowed around it.
Reading the result
Pages are shown in pairs, original on the left and changed version on the right. Red marks words that are only in the original; green marks words that are only in the new version. A reworded phrase shows as red on one side and green on the other. Tick “Show and report only pages with changes” to skip unchanged pages in long documents.
When to compare PDFs
Checking what a counterparty changed in a returned contract, reviewing a new version of a policy or terms of service, proofreading a document after a round of edits, or confirming that a “final” PDF matches the draft that was approved.
The report
The downloaded report puts the two versions of each page next to each other with the same red and green highlights, so you can send it to a colleague or keep it with your records. Neither original file is changed.