Text Diff Checker
Compare two texts line by line and highlight added and removed lines with a count.
How to use this tool
- 1Paste the original text into the left 'Original text' panel.
- 2Paste the modified text into the right 'Modified text' panel.
- 3Click Compare to generate the diff.
- 4Green lines (+) were added; red lines (-) were removed; grey lines are unchanged.
About Text Diff Checker
Spotting the difference between two versions of a document, config file, or code snippet by eye is unreliable. This diff checker uses a Longest Common Subsequence (LCS) algorithm — the same approach used by git diff — to compare two texts line by line. Paste the original text on the left and the modified text on the right, then click Compare. Lines present only in the modified version are shown in green with a + prefix; lines present only in the original are shown in red with a - prefix; unchanged lines are shown in grey. A summary above the diff shows the count of added and removed lines. The diff panel is scrollable for long documents. Developers reviewing config changes, writers comparing document drafts, and anyone who needs to audit what changed between two versions are the primary users. Runs entirely in your browser — no file upload.