Text Diff Checker
Compare two texts and highlight the differences. See added, removed, and unchanged lines at a glance.
Added lines
Removed lines
Unchanged lines
About Text Diff Checker
The text diff checker compares two versions of text and highlights the differences. This is invaluable for reviewing document changes, comparing code versions, checking what was edited in a contract, or finding differences between two very similar texts.
How to Use
- Paste your original text in the left textarea.
- Paste your modified or new text in the right textarea.
- Click "Compare Texts" to generate the diff.
- Green lines are additions (present in modified, not in original).
- Red strikethrough lines are deletions (present in original, not in modified).
- Normal lines are unchanged.
How It Works
This tool implements a line-by-line diff algorithm similar to the classic Myers diff algorithm. It uses the longest common subsequence (LCS) approach to find the minimal set of additions and deletions that transforms the original text into the modified text.
FAQ
A line-by-line diff compares texts line by line. If one line changed, it shows the old version as "removed" (red) and the new version as "added" (green). This is the same approach used by Git for version control.
Yes, this tool works well for comparing any text including code, prose, configuration files, and data. It treats each line as a unit of comparison, just like most code diff tools.
There is no hard limit, but very large texts (thousands of lines) may take a moment to process as the LCS algorithm is O(n²) in the worst case. For typical documents, comparison is near-instant.
No. The entire diff algorithm runs in your browser using JavaScript. Your text is never sent to any server and is completely private.