Compare PDF
Free·No signup·Files never leave your device
How to compare two PDFs in 3 steps
See exactly what changed between two versions of a document.
Add both files
Drop the original first, then the changed copy — they never leave your device.
Click Compare
Pages are paired side by side. Added words are highlighted in blue on the right, removed ones in red on the left.
Review the differences
Switch between differences-only and all pages, and read the summary of changed pages and words.
Why compare PDFs with AmiPDF
Spot every edit in seconds — not by squinting at two windows.
Private by design
Processing happens entirely inside your browser. Nothing is uploaded, stored, or shared — ever.
No signup, no watermark
No account, no email, no limits. Your output comes out exactly as your files went in.
Word-level highlights
Beyond telling you which pages changed, every inserted and deleted word is marked exactly where it sits on the page.
Works on any device
The same fast experience on Windows, Mac, Linux, Android, and iOS — no installation.
When to compare PDF files online
Contract revisions, updated invoices, new versions of reports, translated documents, corrected statements — whenever a new PDF lands on your desk and you need to know precisely what changed since the last one.
Comparison runs entirely on your device, so confidential documents are never uploaded.
Compare PDFs on any platform
AmiPDF runs in your browser — nothing to install, nothing to configure, nothing to update.
Windows
Chrome, Edge, Firefox
macOS
Safari, Chrome
Linux
Any modern browser
iOS
Safari on iPhone, iPad
Android
Chrome, Samsung Internet
Frequently asked questions
How does the comparison work?
The text layer of both files is extracted page by page and compared word by word. Matching words cancel out; words only in the original are highlighted in red, words only in the changed copy in blue.
Can it compare scanned PDFs?
Not yet. The comparison uses the text layer, which scanned images don't have until they are OCR'd. For scanned files, use our redaction or organize tools in the meantime.
What if the two files have different page counts?
Pages are paired by number, and any page that exists in only one file is clearly marked as missing on the other side.
Does it spot image or layout changes?
The automatic diff covers text. Pages where the text is identical but images or styling changed still render side by side so you can eyeball them, but they are not flagged automatically.
Is there a file size or page limit?
No fixed limit — comparison happens in your browser, so the practical limit is your device's memory. Pages render lazily, so large documents stay responsive.
Are my documents uploaded anywhere?
No. Extraction, comparison and rendering all run entirely in your browser.
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