Text Diff Checker
Compare two blocks of text and highlight the differences.
Text Diff Checker — Paste two versions of a text and see exactly what changed: additions in green, removals in red with strikethrough, switchable between line-level and word-level comparison. Great for reviewing document edits, config changes or translated copy. The comparison runs entirely in your browser.
What is Text Diff Checker?
Text Diff Checker is a free online text comparison tool that highlights exactly what changed between two blocks of text. Paste an original and a changed version side by side to spot added text in green and removed text in red with strikethrough, then switch between line-level and word-level comparison to see edits at the granularity you need. Writers, developers, translators, and editors use it to review document revisions, compare config or code changes, proofread copy, and find the difference between two paragraphs without installing anything.
How to use Text Diff Checker
- Paste or type your first version into the Original text area on the left.
- Paste or type the second version into the Changed text area on the right.
- Pick a comparison granularity with the Lines / Words toggle to compare whole lines or individual words.
- Read the color-coded result where additions appear green, removals appear red with strikethrough, and unchanged text stays muted.
- Check the Additions and Removals counters for a quick total of what changed.
- Use Swap to flip Original and Changed, or Clear to reset both fields and start over.
Examples
Word-level edit
Input
Original: The quick brown fox / Changed: The slow brown fox
In Words mode the diff keeps The, brown, and fox unchanged, marks quick as a removal (red strikethrough) and slow as an addition (green). The counters show exactly +1 / -1.
Line-level revision
Input
Original: line one then line two / Changed: line one then line 2
In Lines mode the first line is unchanged, while the second line shows as one removed line plus one added line, so the totals read +1 addition and -1 removal.
Reviewing translated copy
Paste the source paragraph in Original and the proofread translation in Changed, switch to Words granularity, and instantly see every inserted or deleted word highlighted for a fast translation review.
Frequently asked questions
- What is the difference between Lines and Words comparison?
- Lines mode compares the two texts line by line and is best for code, config files, or multi-paragraph documents. Words mode breaks the text into word tokens and highlights individual word changes, which is ideal for proofreading sentences and short copy.
- How are additions and removals shown?
- Added text is highlighted in green, removed text is shown in red with a strikethrough, and unchanged text stays dimmed. The Additions and Removals counters show the totals: line counts in Lines mode and token counts in Words mode.
- What do the Swap and Clear buttons do?
- Swap exchanges the Original and Changed text so you can flip the comparison direction, and Clear empties both text areas to start a fresh comparison.
- Is there a length limit on the text I can compare?
- There is no fixed character limit. The comparison runs in your browser, so practical limits depend on your device. Very large inputs may take longer to compute, but typical documents and code files compare instantly.
- Does my text get uploaded to a server?
- No. The entire comparison runs 100% client-side in your browser. Nothing you paste is sent to or stored on any server, so it is safe for private documents, code, and confidential text.
Related tools
Base32 / Base58 Encode / Decode
Encode text to Base32 (RFC 4648) or Base58 (the Bitcoin alphabet) and decode either one back to text, fully UTF-8 safe and entirely in your browser.
Base64 Encode / Decode
Encode text to Base64 or decode Base64 back to text (UTF-8 safe).
Case Converter & Counter
Change text case and count characters, words and lines.
Code Formatter & Minifier
Beautify or minify HTML, CSS and JavaScript instantly in your browser, with 2-space, 4-space or tab indentation and Terser-powered JavaScript compression.