PDF Comparer
PDFSpot differences between two PDF versions side by side.
PDF Comparer puts two versions of a document side by side and shows you what changed between them. Load both, step through the pages, and spot the edits — the practical way to check what came back from a reviewer, or confirm which draft of a contract you're holding. Both files are rendered locally in your browser, so neither version is uploaded anywhere.
Why use PDF Comparer
100% private
Your PDF files are processed locally and never uploaded.
Instant
No upload or download wait — it runs at the speed of your device.
Free to start
Use it free every day; go Pro for unlimited runs.
No install
Works in any modern browser. No sign-up to begin.
How to use PDF Comparer
- 1Open both PDFs
Drop in the old version and the new one — they're rendered page by page in your browser.
- 2See what changed
Changed areas are clustered into marked regions rather than scattered specks, with a percentage per page, so you can tell a typo from a rewrite at a glance.
- 3Zoom into each change
Step through the detected regions and zoom in, or switch between side-by-side and the highlighted overlay.
Frequently asked questions
How do I compare two PDF files for differences?
Open both versions — the old one and the new one — and every page is rendered and compared in your browser. Changed areas are marked and each page gets a percentage changed, so you can see at a glance which pages moved and which are untouched.
Does it show exactly what changed on the page?
Yes. Rather than reporting that something changed somewhere, changed pixels are grouped into regions you can step through and zoom into — so a moved figure or a single altered number is findable instead of being a few red specks on a dense page.
Can it compare scanned PDFs, not just text ones?
Yes, because the comparison is visual rather than text-based. Pages are rendered and compared as images, so two scans, or a scan against a digital original, still produce a usable diff — where a text-only comparison would find nothing to read.
Are my documents uploaded to compare them?
No. Both files are rendered and compared entirely in your browser, which matters more here than almost anywhere else: the documents people compare are contracts, drafts and reports, and most online comparison services upload both versions to their servers.