What is a text diff checker?
A text diff checker compares an original version with an updated version and marks the lines that changed. It is a practical way to review edits in a draft, notes, a list, simple code or any other line-based text. Additions, removals and unchanged lines are shown together, making it easier to understand what changed without reading both versions side by side from start to finish.
How to compare two texts
- Paste the earlier version into Original text.
- Paste the new version into Revised text.
- Choose whether case or extra whitespace should be ignored.
- Select Compare texts and review the marked lines.
- Copy or download the revised version when you are ready.
Green lines are present in the revised version but not the original. Red lines were removed from the original, while neutral lines match in both versions. A replacement generally appears as one removed line followed by one added line. The summary above the result counts each kind of line so you can quickly see the scale of the revision.
Matching options
Ignore letter case treats words such as “Title” and “title” as the same while keeping the revised text visible in the result. Ignore extra whitespace trims the ends of a line and treats runs of spaces as one space during the comparison. These options are useful for copy that has been reformatted but has not changed in meaning. Leave them off when punctuation, capitalization and spacing are important parts of the review.
This checker compares complete lines, not individual words within a line. That keeps the output readable for lists and drafts. If only one word changes in a long line, that line will be marked as removed and the revised line as added. For the clearest result, place separate ideas or list items on their own lines before comparing.
Private comparison in your browser
Both versions are processed locally with JavaScript. They are not uploaded, stored or sent to a server by this tool. The comparison is limited to 600 lines per text box so it remains responsive on typical devices. Keep a saved copy of important material and inspect the resulting changes before publishing, importing or replacing a source file.