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Compare two texts line by line and highlight additions and removals. Switch between unified and side-by-side views — copy the diff output instantly.
Display Options
Whitespace
Paste two texts and click Compare
Compare two versions of text in your browser. Text Diff Checker finds the longest common subsequence of lines, then reports added, removed, and unchanged lines. Use unified output for a compact review or side-by-side output when comparing the original and modified versions separately.
The checker splits each input at line breaks and preserves line order. Matching lines are treated as unchanged. When a line exists only in the first input, it is marked removed; when it exists only in the second input, it is marked added. This produces a minimal line-oriented diff without requiring a programming language parser.
Unified output uses familiar prefixes:
| Prefix | Meaning |
|---|---|
+ | Line added to modified text |
− | Line removed from original text |
| Space | Line unchanged |
Added and removed line totals appear above the result. Blank lines remain part of the comparison, which makes the tool useful for formatting and document review as well as source code.
Enable the whitespace option when indentation or trailing spaces should not create a difference. The option trims each line before comparison. It does not perform character-level comparison, collapse internal spaces, or change the text shown in either input. Leave it disabled when whitespace carries meaning, such as Python indentation, Markdown formatting, or fixed-width data.
Pasted text stays in the page while comparison runs locally. No account, upload, or language-specific parser is required. For sensitive source code or documents, this local workflow avoids sending content to a remote comparison service.
const port = 3000;
startServer(port);
const port = 8080;
startServer(port);
The unified result identifies the first line as removed and the replacement as added. The side-by-side view shows each version as its own copyable output.
For command-line workflows, Git remains useful for repository history and patches:
git diff -- file.ts
For a quick browser comparison, paste the old and new content into this tool. It is language-agnostic, so the same process works for prose, source code, structured text, and generated files.
Does the checker compare characters? No. It compares complete lines. Use a character-level editor when individual word or character changes need inline highlighting.
Does it modify my input? No. Inputs remain editable, and the result is computed only when Compare is clicked. Enable whitespace ignoring before comparing when outer spaces should be excluded.
This website and utility are provided for general informational, calculation, and educational purposes only. Always verify critical computation outputs prior to professional deployment or financial use. See our Terms of Service and Privacy Policy for full governance details.