PDF Text Compare
Diff the textual content of two PDFs with unified output and a similarity score.
Compare two PDFs textually in your browser. Free PDF diff with unified output and similarity score — no uploads.
Calculator Inputs
About Compare PDFs
Diff the textual content of two PDFs with unified output and a similarity score.
Upload two PDFs to extract both text layers and align them line by line: additions (+), deletions (−), and a Dice similarity percentage. Output caps at 100 changed lines for readability.
Comparison is textual — layout, images, and fonts are ignored, and scanned PDFs need OCR first. Files stay in your browser.
Where it is used
Spotting contract revisions, comparing report drafts, verifying generated documents, and plagiarism triage.
How to use the Compare PDFs
- First PDF — select a file (application/pdf,.pdf) — Up to 50 MB each. Files never leave your browser..
- Second PDF — select a file (application/pdf,.pdf) — Up to 50 MB each..
- Calculate — press the Calculate button to see the result instantly above.
Formula
Extract both text layers → line LCS diff → Dice similarity 2·LCS/(A+B).
Examples
Example
Frequently Asked Questions
- Layout changes but same text — what shows?
- Near-100% similarity with few or no line diffs. This tool compares words, not pixels or positions.
- Can it compare scanned PDFs?
- Only after OCR. Without a text layer both sides extract empty and compare as identical-blank.
- What does 87% similar mean?
- The Dice coefficient over lines: twice the shared lines over the total. Small edits to long documents stay in the high 90s.