Comparing PDFs is not just spotting different pixels. A revised contract can move a paragraph without changing a word, or change one number while every line shifts. A good comparison separates meaningful edits from layout noise.
Step by step
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1
Upload your files
Drag your PDFs onto the box, or click Choose files. The list can be reordered before you run anything.
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2
Run it and download
Press Compare PDF and the page shows progress while it works. When it finishes you get a download link — nothing is emailed and nothing is stored longer than it needs to be.
What the comparison looks for
The Compare tool aligns pages and highlights text that was added, removed or changed. It is deterministic: the same two files produce the same result, with no AI guesswork. That makes it suitable for contracts, reports and revisions where you need to explain every difference.
Prepare the two versions
Compare the original and the revised file, not two exports made with different settings. If one side is a scan, run OCR first so both documents have text to compare. Keep the page count and orientation as close as possible; a page inserted early will shift every later page and make the diff look larger than it is.
Read the diff in context
Start with the summary, then open each changed page and read the surrounding paragraph. A moved sentence is not the same as a changed one. Check numbers, dates, names and negations twice. Export or save the comparison report with the revised document so the approval has a record of what was reviewed.
Good habits for Compare PDF
- Page thumbnails are tap-friendly, so you can reorder and delete on a phone.
- Every tool works on a copy — your original file is never modified.
- Use Split by text when a document has no bookmarks to split on.
Common questions
Is this tool free?
Yes. Every tool on this site is free to use, with no sign-up, no watermark and no daily task limit.
Do I need to install anything?
No. The tools run in your browser and are processed by this server.
What happens to my files?
They are stored under an unguessable id and swept automatically after a couple of hours. Nothing is shared or indexed.
Does it work on a phone?
Yes. The page pickers and editors are built for touch, so dragging, rotating and selecting pages all work without a mouse.
What does Compare PDF do exactly?
Drop the original and the revised file: one runs the diff and lists the key changes — numbers and dates first.
Can I compare a scanned PDF with a text PDF?
Run OCR on the scan first. Without a text layer there is little for a textual comparison to align.
Does Compare change either PDF?
No. It reads both files and produces a comparison; the originals are untouched.
Why does a moved paragraph show as a change?
Layout shifts can affect alignment. Read the page in context — a paragraph that only moved is different from one whose wording changed.