How to compare PDF files
- 1 Drop the original PDF in the first box and the changed version in the second.
- 2 Choose whether to ignore upper and lower case, and whether to show only the changes.
- 3 Press Compare PDFs.
- 4 Read the highlighted differences and the summary of words added and removed.
Reviewing changes efficiently
Start with the summary, then read only the changed parts. For a closer look at either version, open it in the PDF Reader; to copy the full text, use PDF to Text.
- Ignore case when only wording matters.
- Layout changes can show as small differences.
- Scanned PDFs have no text to compare.
Features
Word-by-word comparison
See every added and removed word.
Change summary
Words added, words removed and pages changed.
Private
Both files are read in your browser; nothing is uploaded.
When to use it
Contracts and agreements
Check what the other side changed in a new draft before signing. Then sign it with Sign PDF.
Policies and terms
See what changed between two versions of terms, policies or manuals.
Academic work
Compare drafts of an essay or thesis to review edits. To compare plain text instead, use the Diff Checker in our text tools.
Reports and quotes
Spot changed figures and wording in updated reports and price quotes.
Related PDF tasks
Frequently asked questions
What does the comparison check?
It compares the text of both PDFs word by word. Changes to wording, numbers and punctuation are shown. Changes to images, colours, fonts or layout are not detected.
Can it compare scanned PDFs?
Scanned PDFs contain pictures of text, so there is no text to compare. The tool tells you when a file has no text.
Why are some unchanged parts highlighted?
PDFs store text in pieces, and a change in layout, such as a new line break or a moved column, can make text appear in a different order. Small reflows can show up as changes.
Does it compare page by page?
It compares the whole document as one text, with page markers, so inserted or deleted pages do not throw off the rest of the comparison.
Can I ignore capital letters?
Yes. Tick Ignore upper and lower case to treat Apple and apple as the same.
Is there a size limit?
There is no fixed limit, but very long documents with many changes can take a few seconds to compare.
Can I compare Word documents?
Convert them to PDF first with Word to PDF, then compare. Or paste both texts into the Diff Checker in our text tools.
Can I download the comparison?
Copy the highlighted text, or print the page to PDF from your browser to keep a record.
What is the quickest way to review a long contract revision?
Run the comparison with only the changed parts shown, read the summary of words added and removed, then open each page with changes in the reader to check the context before you agree to the new version.
Are my PDFs uploaded?
No. Both documents are read and compared in your browser, so confidential drafts stay on your device.
How this tool works. These PDF tools run entirely in your browser using two widely used open-source libraries: PDF.js, the PDF engine built into Firefox, to read and render pages, and pdf-lib to create and edit files. Each tool is tested with typed documents, phone scans and photo-heavy files before it goes live, and nothing you open is sent to a server.
Built and reviewed by Hamza Farooq, founder and lead developer
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