The fastest way to see changes between two PDF, DOCX, or text files.
- let theme = "light";
initApp(theme);
// legacy config
+ const theme = "dark";
initApp(theme);
+ applyDarkMode();
Free Online Tools
All tools run entirely in your browser — no uploads, no servers, no data stored. Instant, private, free.
Step-by-Step Guide
Upload two documents, click Compare, and instantly see every difference highlighted — side by side or combined. No software needed, no account required.
Files never leave your browser. Zero server uploads ever.
Client-side PDF.js & Mammoth.js — no waiting for servers.
PDF, DOCX, DOC, PPTX, and plain text — all in one tool.
Drag and drop your original file into the left panel and the modified file into the right panel — or click "Choose File" to browse. Supported formats include PDF, DOCX, DOC, PPTX, and plain text. You can also paste text directly into either panel for instant comparison.
Hit the "Compare" button to run the diff engine. Text is extracted from your files using PDF.js for PDFs and Mammoth.js for Word documents, then compared using the Myers diff algorithm — word by word, instantly in your browser.
Every change is color-coded for instant scanning. Added text appears in green and removed text in red. In Combined view, deletions show as strikethrough inline with insertions highlighted. Use the navigation arrows to jump between changes.
Click "Export" to download a plain-text report listing every addition, deletion, and modification with line references and a total change count. Perfect for attaching to pull requests, legal redline submissions, or academic revision records. No data is retained after you close the tab.
Side-by-side diff view highlights every added (green) and removed (red) word inside PDF, DOCX, and plain text files — fully private, fully browser-based.
Who Uses This Tool
From developers reviewing configs to lawyers redlining contracts — anyone who needs to know exactly what changed between two file versions.
Compare configuration files, JSON responses, SQL migration scripts, or any plain-text code without opening a terminal. Paste two versions and see exactly what changed — variable names, values, and operators — faster than running git diff.
Upload two PDF versions of the same document — contracts, reports, invoices, or policy documents. Text is extracted via PDF.js and every changed sentence, paragraph, or clause is immediately highlighted without any plugin or desktop software.
Compare contract versions, terms of service updates, privacy policy amendments, or compliance filings. Every modified clause, added provision, and removed sentence is flagged — producing a reliable redline in seconds without manual markup or expensive software.
Reconcile two team members' edits on the same DOCX or PDF without needing to enable Track Changes or set up version control. Compare meeting notes, project specs, or design briefs before finalizing — great for remote teams sharing files by email.
Compare thesis drafts, research paper revisions, or annotated bibliographies across submission rounds. See exactly which sentences were reworded, added, or cut after supervisor feedback — no account needed, no citation data ever uploaded.
Maintain multiple tailored versions of your résumé or cover letter and verify edits before submitting. Compare two DOCX or PDF versions to confirm your targeted changes landed correctly — without manually hunting through file versions one by one.
Format Deep Dive
Different document types have different strengths for comparison workflows. Here's everything you need to know.
| Feature | Side-by-Side View | Combined View |
|---|---|---|
| Best for | Reviewing two distinct versions simultaneously | Final proofreading and change summaries |
| Deletions shown as | Red background on left panel text | Red strikethrough inline in unified view |
| Additions shown as | Green background on right panel text | Green highlight inline in unified view |
| Reading flow | ✅ Easy to compare full context | ✅ Single linear document flow |
| Long documents | ✅ Best — scroll both panels together | ⚠️ Can become dense with many changes |
| Legal redlining | ⚠️ Requires focus across two panels | ✅ Industry-standard tracked-changes style |
| Export output | Plain text diff with line numbers | Unified plain text diff report |
FAQ
Everything you need to know about our free file comparison tool.
Yes, completely. Everything runs in your browser using PDF.js, Mammoth.js, and a JavaScript diff engine. Your files never reach any server. No sign-up required, no data stored — you can verify this by running a comparison while fully offline.
PDF (text-based), DOCX, DOC, PPTX, and plain text are fully supported. For scanned PDFs or image files, use our Image to Text (OCR) tool first to extract content, then paste the result into either comparison panel.
We extract plain text from your files using PDF.js (for PDFs) and Mammoth.js (for Word documents), then run the Myers diff algorithm at the word level — the same method used by Git. This finds the minimum set of changes needed to transform one document into the other.
Combined view merges both documents into a single unified view — deletions appear as red strikethrough and insertions as green highlights inline. It replicates the traditional tracked-changes style ideal for legal redlining and final proofreading.
Scanned PDFs contain images rather than selectable text, so they cannot be compared directly. Use our Image to Text tool to run OCR on the scanned document first, then paste the extracted text into either panel as plain text.
Yes. Click the Export button to download a plain-text diff report listing every addition, deletion, and modification with line references and a total change count. Ideal for attaching to pull requests, legal submissions, or academic revision logs.
There are no enforced limits. Very large documents (50+ pages or 10,000+ lines) may take a moment to process depending on your device. Most standard documents process instantly. Since everything runs locally, performance is determined by your hardware.
Track Changes only works if changes were recorded while editing in Word. Our tool compares any two file versions — even if Track Changes was never enabled — by extracting their text and computing the diff on the fly, with no Microsoft account or subscription needed.
Explore More
All tools are browser-based, free, and require no sign-up.
Text & Comparison
Image Conversion
Optimization
Your documents never leave your device. No account needed. No watermarks. No limits. Upload two files and see every difference highlighted in seconds.