Compare two texts and instantly see what changed. Additions highlighted in green, deletions in red.
Original Text
New / Revised Text
■ Added■ Removed
Words in original: 0+ 0 words added− 0 words removed
How to Use
Paste original text in the left box — this is the baseline version.
Paste revised text in the right box — this is the updated version.
Click Compare to see additions (green) and deletions (red) highlighted instantly.
Review the word count stats to see how many words were added or removed.
What Is a Text Diff Tool?
A text diff tool (diff checker) compares two versions of text and highlights the differences. Additions are shown in green, deletions in red, making it easy to see exactly what changed between drafts, code revisions, or document versions.
Perfect for writers comparing drafts, developers reviewing code changes, editors tracking revisions, or anyone who needs to compare two versions of any text.
How It Works
The tool uses a longest common subsequence (LCS) algorithm to compare the two texts word by word. It identifies which words exist in both versions and which were added or removed, then renders the result with color-coded highlighting.
All comparison happens entirely in your browser — your text is never sent to any server.
Tips
Compare AI outputs: If you ask an AI to rewrite text, paste original and revised versions here to see exactly what changed.
Track edits: When collaborating on documents, use this tool to verify that only intended changes were made between versions.
Code review: For quick code diffs when you don't want to set up a full git diff, just paste two versions.
How to Use the Text Diff Checker
Paste your original text version into the left textarea — this is your baseline or "before" content. Paste the revised or updated version into the right textarea. Click the Compare button and the tool instantly highlights every difference: new text appears in green, removed text appears in red with strikethrough formatting. The stats panel shows the original word count, number of words added, and number of words removed. Use the Clear button to reset both textareas and start a new comparison.
Common Use Cases for Text Comparison
Content Editing: Editors and writers can compare article drafts to verify that revisions match what was requested. Instead of reading both versions side by side, the diff tool highlights every insertion and deletion so nothing slips through unnoticed.
AI Output Review: When using AI writing tools, paste the original text alongside the AI-generated rewrite. The diff makes it immediately obvious what was changed, added, or removed, helping you catch AI hallucinations or unwanted tone shifts.
Code Review Without Git: If you receive code snippets via email, chat, or a shared document, paste the old and new versions into this tool for a quick visual diff. It is faster than setting up a git diff for a single file comparison.
Legal & Contract Review: Compare different versions of legal clauses, terms of service, or contract language. Word-level highlighting ensures that even small but significant wording changes are caught before signing.
Tips for Effective Text Diffing
Always Paste the Original First: Get in the habit of putting the baseline version in the left box. The comparison algorithm identifies additions and removals relative to the left text, so consistent placement prevents confusion.
Use for Proofreading: After making edits to your own writing, paste the pre-edit and post-edit versions. This helps you spot unintended deletions — sometimes you accidentally remove a sentence you meant to keep.
Check Plagiarism Edits: When rewriting content to avoid plagiarism, use the diff tool to confirm that enough of the text has been significantly restructured rather than just superficially changed with synonym swaps.
Frequently Asked Questions
Is this tool free to use?
Yes, completely free. No registration, no login, and no subscription required.
Is my data safe?
Yes. All processing happens entirely in your browser — your input never leaves your device and is not sent to any server.
Does this tool work on mobile devices?
Yes. The tool is fully responsive and works on smartphones, tablets, and desktop computers.
How accurate is the comparison?
The tool uses a standard longest common subsequence algorithm to compare word by word, providing highly accurate results.
Can I compare large documents?
Yes. The tool handles documents of significant length entirely in your browser. There are no server-side limits on text size. For very large documents, the comparison may take a few seconds depending on your device's processing power.