Online Tool Store
Text Diff Word-Level Highlighter
Compare two versions of a text and highlight exactly which words were added or removed, not just which lines changed, with a live word-level diff.
🔒 This tool runs entirely in your browser. Your files are never uploaded to a server.
Example shown — added words are underlined green, removed words are struck through red.
How the Text Diff Word-Level Highlighter works
- Paste the original text on the left and the revised text on the right.
- Both are split into a stream of individual words and spaces.
- A longest-common-subsequence diff aligns matching words and highlights everything that was added or removed in between.
Why word-level matters
Editors, translators, and writers often care about exactly which words changed inside a paragraph, not just which lines. Word-level highlighting makes a single-word edit ("red" instead of "brown") visually obvious without re-reading the whole sentence.
FAQ
How is this different from a line-level diff?
A line diff marks a whole line changed even if only one word moved. This tool tokenizes both texts into individual words and whitespace, then runs a longest-common-subsequence diff at the word level, so a single edited word inside a long sentence is highlighted on its own without flagging the entire sentence.
How are additions and removals shown?
Words only in the revised text are underlined in green; words only in the original text are struck through in red. Unchanged words are shown normally so the flow of the sentence stays readable.
Does word order matter?
Yes — this is a positional diff, not a bag-of-words comparison, so moving a word to a different place in the sentence will typically show up as one removal and one addition rather than being recognized as an unchanged word.
How we compare
| Feature | Online Tool Store | Line-level diff tools | Word processor "track changes" |
|---|---|---|---|
| Word-level precision | ✓ | ✗ | ✓ |
| No document upload | ✓ | ✓ | ✗ |
Great for quick paragraph comparisons; for a full editable document with accept/reject changes, use your word processor's built-in track changes.