How to compare two PDFs
To compare two PDFs, open the Compare PDF tool, add both files, and PDFER extracts the text from each and highlights what was added or removed — all in your browser, so neither document is uploaded.
What it detects
Compare works on the text content, showing added and removed lines between the two versions — ideal for catching edits in contracts or drafts.
Because it reads the text layer, scanned/image-only PDFs should be run through OCR first so there's text to compare.
Tools mentioned in this guide
Frequently asked
- Are both PDFs uploaded to compare them?
- No. Text extraction and the diff both run in your browser, so neither file leaves your device.
- Can it compare scanned PDFs?
- It compares text, so run scanned files through OCR first to give it a text layer to work with.