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Compare PDF

Compare PDF extracts the text from two documents, diffs them word by word, and returns a side-by-side HTML report highlighting every insertion, deletion and change.

About Compare PDF

Contract revisions arrive without a change log more often than anyone would like. Version four looks the same as version three until you find, on page eleven, that a notice period moved from thirty days to ninety. Reading both documents in parallel is slow and unreliable, because the eye skims exactly the small numeric changes that matter most in a negotiation.

This tool compares the extracted text rather than the pixels, which means formatting noise, fonts and page breaks do not drown the result in false positives. The requirement that follows from that: both files need a real text layer. A scanned PDF is a picture of words, so run OCR on it first or the comparison will find nothing to read on that side.

How to compare pdf

  1. Upload the original PDF as the first file.
  2. Upload the revised PDF as the second file to compare against it.
  3. Click the compare button and wait while both documents are extracted and diffed.
  4. Open or download the side-by-side HTML report and review the highlights.

Why use this tool

Word-level diff

Changes are highlighted word by word rather than line by line, so a single altered figure inside a long clause is impossible to miss.

Text, not pixels

Comparing extracted text means a font change or a shifted page break does not flood the report with differences that are not real edits.

Side-by-side report

The output is an HTML page showing both versions in parallel with changes marked, so you can scroll one document against the other.

Frequently asked questions

Does this compare how the pages look, or what they say?
What they say. The tool extracts text from both files and diffs the words, so it reports real content changes. A pixel comparison would flag every font substitution and reflow, which buries the handful of edits that actually matter in a revised contract.
What if one of my PDFs is a scan?
A scan holds an image of text, not text, so there is nothing to extract and the comparison will come back empty or badly incomplete. Run OCR on the scanned file first to build a text layer, then compare. Both documents need real text for the diff to work.
What do I get at the end?
A side-by-side HTML report with both versions in parallel and the changed words highlighted, so you can scroll through and see insertions and deletions in context. Open it in any browser, and print it to PDF if you need to circulate the result.
Can it compare documents with different page counts?
Yes. The diff works on the text sequence rather than on matched page pairs, so an added or removed section is reported as inserted or deleted content. Very large structural changes produce a longer report, since more text differs between the two versions.
How does it handle moved paragraphs?
A relocated block usually shows as a deletion in one place and an insertion in another, rather than as a single move. That is a normal limitation of sequence-based diffing. The content is still fully accounted for, so nothing goes unreported, but you read it as two entries.

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