Text Diff Checker
Paste two versions of a text to see exactly what changed. Removed lines are shown in red, added lines in green, and the individual words that differ are highlighted inside each changed line.
About this Text Diff Checker
A diff checker compares two pieces of text and shows you what changed between them. Paste the earlier version into Original text, paste the newer version into Changed text, and click Compare Text. The tool lines the two versions up, keeps the parts that match, and marks everything else: lines only in the original are removed, lines only in the new version are added, and lines that were edited are shown as a pair so you can read the before and after together.
The comparison is smarter than a line-by-line check. It finds the longest sequence of lines the two texts have in common, which means inserting a paragraph near the top does not make every line below it look changed — only the genuinely new line is flagged. Inside each edited line, a second pass compares word by word and highlights just the words that differ, so a one-word correction in a long sentence is easy to spot.
The options let you ignore differences you do not care about. Ignore letter case treats "Total" and "total" as the same. Ignore leading and trailing spaces is useful when indentation has changed but the content has not. Ignore blank lines skips empty lines, which helps when formatting differs. Original line numbers are always kept, so the numbers still match the text in your editor. Switch between Side by side and Unified to read the result the way you prefer, use Swap to reverse the comparison, and Copy Diff to copy a plain-text version with the usual plus and minus prefixes.
People reach for a diff checker when proofreading two drafts of an article or contract, checking what a colleague edited in a document, comparing configuration files or code snippets, verifying that a copy-and-paste transfer did not lose anything, or reviewing translated text against the source. The similarity figure gives a quick sense of how far apart the two versions are before you read the detail.
Note: Everything is compared inside your browser and nothing is uploaded, so you can safely paste private text. Very large inputs are limited by your device's memory; if you compare tens of thousands of lines at once the tool asks you to work in smaller sections instead.