Diff Checker — Compare Text Online Free
Paste two texts and compare them line by line. See additions, removals, and modifications highlighted instantly.
How to diff checker
- 1Paste your original text into the left textarea
- 2Paste the modified text into the right textarea
- 3Click the Compare button to see the differences
- 4Toggle between inline and side-by-side views for your preferred layout
About This Tool
A diff checker highlights the differences between two pieces of text, making it easy to see what was added, removed, or changed. This is essential for code reviews, comparing configuration files, checking document revisions, and verifying database migrations.
The tool performs a line-by-line comparison and color-codes the results: green for additions, red for removals, and yellow for modified lines. Line numbers are included for easy reference. You can switch between an inline unified view and a side-by-side split view depending on your preference.
Statistics show the total number of added, removed, and unchanged lines, giving you a quick summary of how much changed between the two versions. All comparison happens in your browser with no data sent to any server.
Frequently Asked Questions
The tool uses a line-by-line comparison with a longest common subsequence (LCS) approach, similar to the classic Unix diff algorithm. It identifies the minimal set of changes between the two texts.
Yes. The tool works with any plain text including source code, configuration files, JSON, XML, SQL queries, and prose. Simply paste the contents of each file.
Green highlights indicate lines that were added in the modified text. Red highlights indicate lines that were removed from the original. Yellow indicates lines that exist in both but with changes.
There is no hard limit, but very large texts (over 100,000 lines) may cause the browser to slow down since the diff is computed in-browser. For typical use cases the tool handles texts of any reasonable size instantly.