What is a Diff Checker?
A diff checker (difference checker) is a tool that compares two versions of text and highlights what has changed, been added, or removed. The term "diff" comes from the Unix command-line tool that compares files line by line. Diff checkers are essential for writers, editors, developers, and anyone who needs to track changes between document versions.
Whether you're reviewing edits to an article, comparing code versions, checking student submissions against originals, or verifying document changes, a diff checker saves hours of manual comparison and helps you spot even subtle differences instantly.
How to Use Our Diff Checker
- Paste your original text in the first text area
- Paste the modified or new version in the second text area
- Click "Compare Texts" to see the differences
- Review highlighted changes: red for removed/changed text, green for added/changed text
- Use the side-by-side view to understand what changed and where
Common Use Cases
- Content Editing: Review edits made to articles, blog posts, or documents
- Code Review: Compare different versions of code to see what changed
- Plagiarism Detection: Compare submitted work against source material
- Legal Documents: Verify changes in contracts or legal agreements
- Translation Verification: Ensure translations match the original text
- Configuration Files: Compare different versions of config files to spot changes
Understanding Diff Results
- Removed/Changed (Red): Text that exists in the original but was removed or modified in the new version
- Added/Changed (Green): Text that was added or modified in the new version
- Unchanged: Text that remains the same in both versions (displayed normally)
Best Practices
- Ensure proper formatting: Copy text exactly as it appears to get accurate comparisons
- Check whitespace: Be aware that differences in spaces or line breaks will be detected
- Review context: Always review changes in context to understand their impact
- Verify important changes: For critical documents, manually verify important changes
Frequently Asked Questions (FAQ)
Is this diff checker free?
Yes, our diff checker is completely free to use. Compare unlimited text without any restrictions or registration required.
How accurate is the comparison?
Our diff checker compares text character by character and line by line, providing highly accurate results. It detects additions, deletions, and modifications, though very complex formatting changes may require manual review.
Can I compare files larger than text?
Our tool is designed for text comparison. Very large documents (tens of thousands of words) may work, but processing could be slower. For extremely large files or binary files, consider using specialized diff tools.
Is my data safe?
Yes. All comparison happens entirely in your browser. Your text never leaves your computer—it's never sent to any server. This ensures complete privacy for sensitive documents.
Does it work with formatted text (HTML, Markdown)?
Our tool compares text as-is, so it will detect differences in HTML tags, Markdown syntax, or any formatting codes. For visual formatting differences in rendered content, you may need specialized tools.