Free Online Text Diff Tool – Compare & Highlight Text Differences
Compare Two Texts and See Differences Instantly
What is a Text Diff Tool?
A text diff tool (also known as a text comparison tool or difference checker) is a utility that compares two pieces of text and highlights the differences between them. Our free online text diff tool allows you to quickly identify additions, deletions, and modifications between two versions of text.
Whether you're comparing code revisions, document versions, configuration files, or any other text content, this tool provides a clear visual representation of what has changed. The tool works entirely in your browser, ensuring your sensitive data remains private and secure.
Unlike simple text comparison that just tells you texts are different, our diff tool shows you exactly what changed, where it changed, and provides detailed statistics about the modifications. This makes it invaluable for developers, writers, editors, and anyone who needs to track changes in text documents.
How to Use the Text Diff Tool
- Paste your original text: Copy and paste the first version of your text into the "Original Text" box on the left.
- Paste your modified text: Copy and paste the second version into the "Modified Text" box on the right.
- Select comparison mode: Choose between character-level, word-level, or line-level comparison depending on your needs:
- Character-level: Shows differences at the character level, ideal for spotting minor changes in text or code.
- Word-level: Highlights changes by words, best for comparing documents and articles.
- Line-level: Compares entire lines, perfect for configuration files and source code.
- Click "Compare Texts": The tool will instantly analyze both texts and highlight the differences.
- Review the results: Green highlights indicate additions, red shows deletions, and unchanged text remains unformatted.
- View statistics: See the number of additions, deletions, and changes at a glance.
- Additional options: Use "Swap Texts" to reverse the comparison, "Clear All" to start over, or copy either text version to your clipboard.
Pro Tip: For best results with code comparison, use line-level mode. For document proofreading, word-level mode is usually most effective.
Key Features
- ✅ Multiple Comparison Modes: Character, word, and line-level diff algorithms to suit different use cases.
- ✅ Color-Coded Highlighting: Clear visual distinction between additions (green), deletions (red), and unchanged text.
- ✅ Side-by-Side View: Compare both texts simultaneously with synchronized scrolling for easy navigation.
- ✅ Detailed Statistics: See exact counts of additions, deletions, and changes.
- ✅ Client-Side Processing: All comparisons happen in your browser—your text never leaves your device.
- ✅ No File Size Limits: Compare texts of any length, from short snippets to long documents.
- ✅ Copy & Swap Functions: Easily copy either version or swap positions for different perspectives.
- ✅ Mobile-Friendly: Works seamlessly on desktop, tablet, and mobile devices.
- ✅ No Registration Required: Start comparing texts immediately without creating an account.
Common Use Cases
Software Development & Code Review
- Compare different versions of source code files
- Review code changes before committing to version control
- Identify what changed between two code snippets
- Debug configuration files by spotting differences
- Review pull request changes in detail
Document & Content Management
- Compare two versions of a document or article
- Track changes in contracts or legal documents
- Review editorial revisions and edits
- Verify translations against original text
- Check for plagiarism by comparing similar texts
Configuration & System Administration
- Compare server configuration files before and after changes
- Audit changes in system settings
- Verify environment variables or .env files
- Compare database schemas or SQL dumps
- Review log files for differences
Education & Learning
- Compare student submissions to detect similarities
- Review corrections and feedback on written work
- Track progress by comparing drafts
- Learn from code examples by seeing what changed
Understanding Comparison Modes
Character-Level Comparison
This mode compares texts character by character, making it extremely precise. It's ideal when you need to spot even the smallest changes, such as:
- Single character typos or corrections
- Whitespace changes in code
- Punctuation modifications
- Case changes (uppercase to lowercase)
Best for: Code snippets, technical writing, data validation
Word-Level Comparison
This mode treats each word as a unit of comparison, providing a balance between detail and readability. Perfect for:
- Document revisions and editing
- Article comparison
- Content updates
- Proofreading and copy editing
Best for: Documents, articles, essays, reports
Line-Level Comparison
This mode compares entire lines at once, making it easy to see structural changes. Excellent for:
- Source code comparison
- Configuration files
- CSV or data files
- Scripts and automation files
- Lists and structured text
Best for: Code files, configs, structured data, scripts
Tips for Effective Text Comparison
💡 Choose the right mode: Start with word-level for general text and line-level for code. Use character-level only when you need extreme precision.
💡 Remove formatting: If comparing formatted documents, paste them as plain text to avoid false differences from invisible formatting characters.
💡 Normalize line endings: Different operating systems use different line endings (Windows: CRLF, Unix: LF). If you see unexpected line differences, this might be the cause.
💡 Privacy first: Our tool runs entirely in your browser. Your text is never uploaded to any server, ensuring complete privacy for sensitive documents.
💡 Large files: While our tool can handle large texts, very large files (100,000+ characters) may slow down your browser. Consider comparing smaller sections if performance becomes an issue.
Frequently Asked Questions (FAQ)
Is my text sent to a server?
No. All text comparison happens entirely in your web browser using JavaScript. Your text never leaves your device, ensuring complete privacy and security.
What's the maximum text length I can compare?
There's no hard limit, but very large texts (over 100,000 characters) may slow down your browser. For best performance, compare reasonably sized text segments.
Can I compare code files with this tool?
Absolutely! The line-level comparison mode is specifically designed for comparing source code, configuration files, and structured text.
Which comparison mode should I use?
Use character-level for precise, character-by-character comparison; word-level for documents and articles; and line-level for code and configuration files.
Can I save or export the comparison results?
Currently, you can copy either the original or modified text to your clipboard. For more permanent storage, take a screenshot of the comparison or copy the results.
Does this tool work offline?
Once the page is loaded, the comparison functionality works without an internet connection since all processing happens in your browser.
How accurate is the diff algorithm?
We use a standard Myers diff algorithm, which is the same algorithm used by popular version control systems like Git. It's highly accurate and reliable.
Can I use this for comparing non-English text?
Yes! Our tool supports all Unicode characters, making it perfect for comparing text in any language including Chinese, Arabic, Japanese, and more.