Scan & repair
Compare PDF
See what changed between two versions of a PDF. Added and removed text, page changes and visual differences are highlighted side by side, and neither file is uploaded.
Runs on your device: your file is not uploaded
Original
The earlier version
Up to 50 MB and 200 pages
Revised
The version with changes
Up to 50 MB and 200 pages
What Compare PDF does
Compare PDF takes an original and a revised document and lists every difference it finds. It reports words that were added, removed or replaced. It pairs up pages, so an inserted page does not throw everything after it out of line. And it compares how each pair of pages looks, to catch changes that are not text, such as a swapped image.
Side by side shows both pages with linked highlights; Text changes, Overlay, Visual difference and Blink give other views. Each change can be marked as reviewed, and the comparison can be exported as a PDF or text report.
Both files stay in your browser; nothing is uploaded. Scanned pages have no text to read, so they are compared by appearance unless you turn on Recognize text with OCR.
Is this the right tool?
Good for
- Checking what the other side changed in a contract before you sign it.
- Confirming that only the agreed edits were made between two drafts.
- Finding out whether two files with similar names really hold the same content.
- Proofreading a fresh export against the approved version.
Not the right tool for
- Comparing Word documents. Convert both to PDF first, then compare the PDFs.Word to PDF
- Combining two versions into one document. Applying the differences you want is an editing job.Edit PDF
- Proving two files are identical down to the last byte. The comparison reads text and sampled page images.Guide: text and visual comparison
How to compare two PDFs
Choose the two files
Add the earlier version as the original and the newer one as the revised PDF, each up to 50 MB and 200 pages.
Compare
Select Compare files. Text reading, page matching and the visual check run on your device.
Work through the changes
Step through the change list or use Previous change and Next change. Open Settings to ignore spacing, letter case, outer margins or a region such as a date stamp.
Export a report
Select Export report, choose PDF or Text, then select Download report.
Worked example
Checking a returned contract
Say you sent a supplier a 22-page agreement and it came back with a note saying they made a couple of small changes.
Add your version as the original and theirs as the revised file, then select Compare files. Step through with Next change. Suppose one entry shows the payment term changed from 30 days to 60, and another shows a sentence added to the liability clause; both are highlighted in place.
Their copy also has a different date in every footer, which adds a change on each page. Open Settings, add the footer under Ignored regions, and compare again. The list shrinks to the changes that matter.
Tips for a better result
- Alt+Left and Alt+Right jump to the previous and next change.
- If the files came from different software, turn on Ignore spacing differences to cut out noise from how each program spaces its text.
- Look at the Text checked figures above the pages. Pages with no readable text are scans; turn on Recognize text with OCR and pick the document language.
Compare PDF: questions and answers
Can I compare two scanned PDFs?
Yes. Without OCR, scanned pages are compared by appearance only. Turn on Recognize text with OCR in Settings and choose the language, and wording changes on up to 100 image-only pages are reported too. Recognition can misread characters, so treat names and numbers with care.
Why does Compare PDF report changes when the two documents look the same?
Usually because the files were produced differently. Exporting a document again can change the invisible spacing between words, swap a font, or shift everything by a fraction of a millimeter. Ignore spacing differences and a lower Visual sensitivity remove most of that noise.
Can Compare PDF catch a color change or a very small detail?
Not reliably. The visual check works on sampled grayscale images, so a logo that changed from blue to green, or a single altered digit inside a picture, may not be flagged. Where that matters, use Overlay or Blink view and look closely yourself.
Does it matter which file I pick as the original in a comparison?
Only for how the results are labeled. Text found in the first file but not the second is shown as removed, and text found only in the second as added. If the labels look backward, go back and select Swap versions.