Free PDF Compare Tool - Find Differences Between Two PDFs
Visually compare two PDF documents side by side. Highlights added, removed, and changed text between versions. Browser-based and private.
What is Compare PDF?
Reviewing changes between two versions of a PDF — a revised contract, an updated policy document, or a corrected report — is time-consuming when done manually. Our free PDF Compare tool does it automatically, presenting both documents side-by-side with colour-coded highlights showing exactly what changed.
The tool uses pdf.js to extract the text layers from both PDFs, then performs a character-level diff using JavaScript. Added text is highlighted in green, removed text in red, and unchanged text remains neutral. This gives you a clear, fast visual summary of every textual change.
The side-by-side view synchronizes scrolling so corresponding pages stay aligned as you review. Click on any highlighted difference to jump to that change in both documents simultaneously.
This is essential for contract review, document version control, compliance auditing, and editorial revision tracking. Both PDFs are processed locally in your browser — sensitive legal and financial documents are never uploaded or stored.
Powerful Features
Everything you need in one amazing tool
Text-Level Diff
Performs character-level text comparison using pdf.js text extraction and JS diff.
Side-by-Side View
Both PDFs displayed in synchronized side-by-side panels for easy comparison.
Added Text Highlighted
New text in the second PDF is highlighted in green. See clearly what was added.
Removed Text Highlighted
Text removed in the second PDF is shown in red. Nothing is missed.
Fully Private
Both documents are processed locally. No content leaves your browser.
Change Summary
Summary panel shows total additions, deletions, and page-level change counts.
How It Works
Get started in 4 easy steps
Upload Both PDFs
Select the original PDF and the revised PDF. Both are loaded in your browser.
Run Comparison
Click Compare. Text layers are extracted with pdf.js and diff is calculated.
Review Changes
Additions appear in green, deletions in red, in the synchronized side-by-side view.
Export Report
Download a change summary as a .txt report for documentation or audit trail.
Why Choose Our Compare PDF?
Stand out from the competition
Private Comparison
Confidential contracts and documents never leave your browser. Both PDFs stay local.
Precise Diff
Character-level diff catches even small changes — single word substitutions, number changes.
Easy Navigation
Synchronized scrolling and jump-to-change navigation make reviewing fast and effortless.
No Server Required
Comparison runs entirely client-side. No upload time, no processing delay.
Export Diff Report
Download a full change log as a text report for audit trails, compliance, or version records.
Free & Private
Both documents stay in your browser. Completely free with no account required.
Perfect For
See how others are using this tool
Contract Versions
Compare original contract to final signed version to identify all negotiated changes.
Compliance Auditing
Verify that policy documents or compliance reports have only authorized changes.
Editorial Review
Track edits between manuscript drafts and quickly review author or editor revisions.
Technical Documentation
Compare specification or API documentation versions to track what changed.
Policy Document Review
Verify that policy documents only contain approved amendments between revision versions.
Manuscript Review
Compare paper drafts submitted for journal review against the author revised version.
Frequently Asked Questions
Everything you need to know about Compare PDF
The tool compares the text layer. Scanned PDFs have no text layer — use the OCR tool first to get a text layer, then compare.
Currently the tool performs text-level comparison. Changes to images, fonts, or layout that do not affect text content are not highlighted.
No. Both PDFs are processed entirely in your browser. No content is sent to any server.
The comparison handles different page counts gracefully. Extra pages in either document are flagged as fully added or removed.
Yes. A text-format diff report showing all additions and deletions can be downloaded for your records.
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