How does text comparison work?

The diff tool analyzes two texts line by line and highlights differences: additions in green, deletions in red, and changes in yellow. Perfect for code review and document comparison.

Can I compare source code?

Yes, the diff tool works with any type of text including source code, documents, configurations, and more. It shows exact differences between two versions.

Is it free and private?

Yes, the diff tool is 100% free. All processing happens in your browser, your texts are never sent to any server.

Text Diff / Compare Tool

Compare two texts side by side with highlighted differences for free. Find additions, deletions & changes instantly. Perfect for code review & document comparison.

Processing: local in your browser

Original Text1 lines

Modified Text1 lines

Ignore whitespace

All comparison is done in your browser. No data is sent to any server.

Free Online Text Diff & Compare Tool

Compare two texts side by side with color-coded differences. Find additions, deletions, and changes instantly. Perfect for code review, legal document comparison, version control, and translation verification.

How Diff Comparison Works

Our comparator uses the Longest Common Subsequence (LCS) algorithm to precisely identify differences between two texts. It supports line-by-line and word-by-word comparison. Additions are highlighted in green, deletions in red, and modifications are clearly marked for quick, error-free identification.

Common Use Cases

Code review: compare old and new versions of your code before committing. Legal documents: verify changes between contract versions. Translations: compare original text with translation to detect omissions. SEO: compare meta descriptions or content between page versions.

Local Processing

All processing happens in your browser using pure JavaScript. The texts you compare are never sent to ToolsFree. This avoids an upload to our server, while device and browser security still matter for sensitive documents.

Line vs Word Comparison

Line comparison marks an entire line as changed as soon as anything in it differs, and works well for code or lists where each line is a unit. Word comparison is more granular: it highlights only the specific words that change within a line, which is ideal for prose, contracts, or translations, where a single word can matter. Choose the mode based on how fine-grained you need the result to be.

Comparing Long Texts

Before comparing long texts, it helps to normalize noise such as trailing spaces or line breaks so the real differences stand out. Keep in mind that the tool limits comparison to the first 2,000 lines for performance; if a document is truncated, you are told. For very large files, split the text into sections and compare them in parts.

A worked example

The diff tool comparing two versions of a YAML server configuration in unified view, summarised as 3 lines added, 2 removed and 3 unchanged, with the changed timeout and retry values aligned against their originals. — Two revisions of the same configuration: 3 lines added, 2 removed, 3 unchanged. Line diffs work this way — a changed line is reported as a removal plus an addition, never as an edit — which is why “timeout: 30” becoming “timeout: 5” counts twice. Knowing that stops you from reading a small edit as a large rewrite.

Frequently Asked Questions

How does text comparison work?: The diff tool analyzes two texts line by line and highlights differences: additions in green, deletions in red, and changes in yellow. Perfect for code review and document comparison.
Can I compare source code?: Yes, the diff tool works with any type of text including source code, documents, configurations, and more. It shows exact differences between two versions.
Is it free and private?: Yes, the diff tool is 100% free. All processing happens in your browser, your texts are never sent to any server.

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