Compare Two PDFs: See What Actually Changed
Two files, one question: what changed? Instead of flicking between windows, you get a report that names the wording, the numbers, the dates and the pages that shifted.
What this tool does
Compares two versions of the same document and names every meaningful difference: changed wording, numbers and dates, inserted or removed blocks, and pages that shifted. The result is a report you can read, not a highlight layer you have to interpret.
How it works
Upload the original and the revised file in that order, run the comparison and download the report. Start with the key changes at the top: a figure that moved is usually the reason the document came back. Only two files are compared at a time, and both must carry a text layer — run OCR first on scans. Compare is also available as a paid API route; the FAQ carries the details.
- Add the PDFs in the order you want them handled.
- Run the tool and download the result.
When to reach for it
- A contract came back from the other side. You need to know which clause changed before you sign, not after.
- A drawing or report was reissued. Compare the revision against the copy you already approved.
Questions we get
Can I run Compare from the API?
Yes — POST /v1/compare-pdf is live and costs 5 credits. Send file_a and file_b with a bearer key; the JSON contains stats, changed blocks and key differences. See the API page.
Where it fits
The tools people usually open next to Compare PDF:
- Flip — Mirror PDF pages horizontally or vertically.
- Split in half — Split two page layout scans, A3 to double A4 or A4 to double A5.
- N-up — Print multiple pages per sheet per paper.
Every tool works on a copy, so the original file is never modified. Uploads are stored under an unguessable id and deleted automatically two hours after you last open them; nothing is listed, shared or indexed. More on the security page.