“The difference is where the meaning hides.”
Compare PDF Online
Upload two versions of a document and get back a report PDF that lists what changed on every page — both the text edits and the visual differences a text diff would miss.
- No sign-up, no watermark
- Files encrypted and auto-deleted
- No installation — runs right in your browser
- Fast processing on desktop and mobile
Read our full guide: How to Compare Two Versions of a PDF and Spot Every Change →
How to use Compare PDF online
- 1
Upload your files
Drag and drop or click to select your file(s). Uploads go directly to encrypted cloud storage over HTTPS. (PDF)
- 2
Run the tool: Compare PDF
Processing happens instantly in the cloud — no software to install, works on Windows, Mac, Linux, iOS and Android.
- 3
Download the result
Get your processed file via a secure temporary link. All files are deleted automatically about a day after upload.
Frequently asked questions
What do I actually get back?
A comparison report as a PDF, not a marked-up copy of your document. It opens with each file's page count, then walks page by page listing removed lines prefixed with "-" and added lines prefixed with "+", plus the percentage of pixels that changed on that page.
Why does it check pixels as well as text?
Because a text diff alone misses a swapped logo, a moved table, a changed chart, or a shifted signature block — all of which read as identical text. Rendering both versions and measuring what fraction of the page changed catches formatting and image edits that never touch a word.
What if the two files have different page counts?
That's handled explicitly. Pages beyond the shorter document are reported as existing only in A or only in B, so an inserted or deleted page shows up as itself rather than cascading into a false diff on every page after it.
Is there a limit on how much detail is reported?
Yes — up to 12 changed lines are listed per page, so a heavily rewritten page reports its most significant changes rather than reproducing the whole document. Very long pages are also capped when computing the line-level diff to keep comparison fast.
Can I compare two scanned documents?
Only if they have a text layer. A raw scan is an image, so there is no text to line up and differences cannot be found. Run OCR PDF on both versions first, then compare the results.