Compare two PDFs
Drop one PDF, pick a second, and see what changed in the text. You get a colour-coded report of the lines added and removed. Everything runs in your browser; your files never leave your device.
What this tool compares
It reads the text layer out of both PDFs with pdf.js and runs a line diff between them, the same kind of comparison a code review tool shows. The result marks each line as added in the second PDF, removed from the first, or unchanged. Because it works on the extracted text, it catches wording changes — new paragraphs, deleted clauses, edited sentences — regardless of where they sit on the page. It does not compare the visual layout, fonts, colours, or images: a page that merely moved or was restyled, with the same words, reads as unchanged here.
It is a text diff, not OCR
This tool only compares PDFs that already contain selectable text. A scanned document, or any image-only PDF, has no text layer, so there is nothing for the diff to read — the comparison would come back empty. It does not run optical character recognition to turn pictures of text into text. If you can select and copy text in both PDFs in a normal viewer, this tool can compare them.
Is it private?
Yes. Both PDFs are opened and compared entirely in your browser using pdf.js, a pure-JavaScript engine. Nothing is uploaded, stored, or seen by us, and there is no server involved. The comparison report is generated on your device as a self-contained HTML file you download directly.
Frequently asked questions
- What exactly does this compare?
- It extracts the text layer of both PDFs in your browser and runs a line-by-line diff, then produces an HTML report that marks lines added in the second PDF (green) and removed from the first (red). It compares the words, not the visual appearance — layout, fonts, colours, and images are not part of the comparison.
- Does it work on scanned documents?
- No. A scanned or image-only PDF has no text layer to extract, so there is nothing for the text diff to compare. This tool is not OCR — it does not turn pictures of text into text. It only compares PDFs that already contain selectable text.
- Are my files uploaded to a server?
- No. Both PDFs are read and compared entirely on your device using pdf.js, and the tool keeps working even if you go offline after the page loads. Your files are never sent anywhere, and there is no server involved.
- What do I get back?
- A single self-contained HTML file you can download and open in any browser. It has a small header with the count of added and removed lines, then the colour-coded diff. There is no external dependency, so it renders offline.
- Is it free, and do I need an account?
- It is free with no daily caps and no sign-up. Drop the first PDF, pick the second, and download the comparison.