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PDF compare tool

Drop in two PDF files and get a similarity score, page and word counts, plus the words unique to each document.

Compare two PDFs

Select two PDF files, then press Compare. Text is extracted in your browser.

Comparison result

No comparison yet.

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How the comparison works

Both PDFs are opened in your browser and their text is extracted page by page. The tool counts words, compares the vocabulary of the two documents, and computes a similarity score from the overlap of their word usage.

The score is a word-level Jaccard-style similarity: 100% means the documents use the same words with the same frequencies, 0% means they share nothing.

What it is good for

Use it to check whether two contracts, articles, or reports are near-duplicates, to spot which terms appear in one version but not the other, or to sanity-check that an exported PDF matches its source document.

Scanned PDFs made of images contain no selectable text, so the comparison only works on PDFs with a real text layer.

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PDF Compare Tool FAQs

How is the similarity score calculated?
The tool compares word frequencies between the two PDFs. Shared words raise the score; words that appear in only one document lower it. It measures vocabulary overlap, not sentence order.
Does it show exactly what changed between versions?
It lists the most frequent words unique to each PDF, which usually reveals added or removed sections. For a line-by-line diff of document revisions, a dedicated diff tool works better.
Why does a scanned PDF show zero words?
Scanned PDFs are images, not text. The extractor can only read PDFs with a real text layer. Run the scan through OCR software first, then compare the result.
Is there a file size limit?
There is no hard limit, but very large PDFs (hundreds of pages) take longer because every page is read in your browser. Files under 50 MB compare in seconds on most devices.
Are my PDFs uploaded to a server?
No. Both files are read locally with JavaScript and never leave your device, so confidential contracts and reports stay private.
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