Compare PDF Files Free. Upload Two PDFs and Get a Similarity Score.

The tool compares the text content of each page pair using word-overlap scoring (Jaccard similarity). For each page pair, it calculates: the number of words in common ÷ total unique words across both pages × 100 = similarity percentage.

Here is what the results display shows:

The tool extracts the text content from each page of both PDFs and calculates the word-overlap similarity score for each page pair. For most documents, this takes 5-30 seconds depending on page count and file size. Processing runs entirely in your browser - nothing is uploaded.

The overall similarity percentage appears at the top. Below it, each page pair is displayed side-by-side with its individual score. A score above 85% means the pages are mostly the same text. A score below 50% indicates significant content differences. Review side-by-side thumbnails for a visual comparison of layout and content.

Note: similarity scores measure word overlap, not meaning overlap. A page that has been heavily paraphrased (same meaning, different words) will score low even if the intent is unchanged. A page with identical formatting but different numbers in a table will score high because the non-numeric words match - while the substantive differences (the numbers) may be missed by the text comparison.

Adobe Acrobat Pro includes a Compare Documents function that produces a colour-coded side-by-side comparison with individual change markers. It is powerful but requires a paid subscription. RepetiGo provides a free similarity score alternative:

Document comparison is a frequent need across Indian legal, financial, and administrative workflows:

• Contract version review: Legal teams reviewing redlined contracts between two parties - check which pages changed between the draft sent and the version returned
• Tender document verification: Compare the final submitted tender document against the working draft to confirm no unauthorised changes occurred before submission
• Property document comparison: Compare sale deed drafts between iterations to confirm only the agreed changes were incorporated by the opposite party's lawyer
• Regulatory filing verification: Compare the PDF submitted to a regulator against the approved internal version - confirm the documents are identical before filing
• Academic and research: Compare thesis drafts or research paper versions to identify which sections were substantially revised between rounds of supervisor feedback
• HR policy documents: Compare the current employee handbook against the previous version - identify which policies changed for the annual employee communication

The word-overlap comparison works best on text-based PDFs. Several conditions reduce the accuracy of the similarity score:

• Scanned image PDFs: PDFs created by scanning physical documents have no text layer - only image data. The comparison has no text to compare and falls back to checking whether page images are byte-identical (100% if identical, 50% if different). For scanned PDFs, run them through the OCR PDF tool first to add a text layer before comparing
• PDF/A and complex structured PDFs: Some compliance PDFs and structured forms use non-standard text encoding that reduces extraction accuracy
• Number-heavy documents: Tables of financial data where the key differences are in the numbers (not the surrounding words) may show high similarity despite substantive differences in the underlying values
• Multi-column layouts: PDFs with complex multi-column page layouts may have text extracted in a non-linear reading order, reducing comparison accuracy for column-heavy documents
• PDFs with significant images: Documents where a large portion of the page content is image-based (charts, diagrams, photographs) are compared only on their text content - image differences are not detected

RepetiGo's PDF tools run entirely in your browser. Your PDF is never uploaded to any server - it is processed locally on your device.

• 🔒 Browser-only processing: Your file never travels over any network to any server. No upload occurs at any stage.
• 🔐 No server session: There is no remote processing session, no isolated server workspace. Everything happens inside your browser tab.
• 🚫 No account = no data: No sign-up means we hold zero personal data about you. No file history, no email, no usage tracking.
• 👁️ Content never leaves device: No text, image, or document content is sent to or read by any external system or person.
• ✅ Cleared on tab close: All local working data clears when you close or refresh the tab. Nothing persists on your device or any server.

No - the comparison produces a similarity percentage score. Individual changed words are not highlighted in red or green. The result shows how much the content overlaps as a number, not a visual diff. For word-level change highlighting, Microsoft Word's Compare Documents (File → Compare → Compare) works on DOCX files; for PDF-specific visual diffs, Adobe Acrobat Pro's Compare Documents tool provides colour-coded output.

The comparison works on the text layer of PDFs. Scanned image PDFs with no text layer cannot be meaningfully compared using text analysis - the tool falls back to checking whether pages are byte-identical (score 100%) or different (score 50%), which is not a real textual comparison. For better results with scanned PDFs, run them through the OCR PDF tool at Open OCR PDF to extract and embed a text layer, then compare.

No - exactly two PDFs are compared per session. For multiple comparisons, run the tool once for each pair. There is no batch comparison mode.

A score of 0% means no words in common between the two pages - they share zero text content. This happens when the pages are completely different in wording, or when one or both pages have no text layer and their scanned images also differ. It also occurs when pages exist on one side of the comparison but not the other - missing pages always score 0%.

The comparison results are displayed on-screen - overall score and per-page breakdown. A downloadable comparison report PDF is not generated. To save your results, take a screenshot of the results page or note the key scores manually.

It depends on the context. For confirming a document was not changed between sending and receiving, a high score (95-100%) confirms the documents are identical. For confirming that agreed changes were correctly incorporated into a revised draft, you would expect a score slightly below 100% - and the per-page breakdown helps identify which pages changed as expected.

If PDF A has 10 pages and PDF B has 12 pages, the extra 2 pages in PDF B score 0% (no matching pages in PDF A). The tool handles different page counts - it pairs matching pages and scores unmatched pages as 0% similar. The per-page breakdown shows clearly which pages are paired and which have no match.

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