📄 Diff · Compare text · Instant

Compare text and find differences

Paste two texts side by side and instantly see what changed. Perfect for comparing code, documents, configs, and more.

Line-by-line diff Inline highlights Side-by-side view Free forever
Diff Checker
Enter text in both fields and click "Compare" to see differences
Features

Powerful diff capabilities

Everything you need to compare and understand changes

📊

Line-by-Line Diff

Intelligent comparison algorithm identifies exactly which lines were added, removed, or changed.

🎯

Word-Level Highlights

See precisely which words and characters changed within each line for detailed analysis.

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Dual View Modes

Compare side-by-side for context or inline for a compact view of all changes.

⚙️

Smart Options

Ignore whitespace, ignore case sensitivity, and swap texts with a single click.

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Change Statistics

Get instant counts of additions, deletions, and unchanged lines in your comparison.

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Copy Diff Output

Export results in standard unified diff format with one click for use anywhere.

How It Works

Simple and fast

Get results in seconds with our instant comparison

1

Paste Texts

Paste your original text on the left and modified text on the right.

2

Click Compare

Hit the Compare button to instantly analyze the differences.

3

View Results

See detailed line-by-line and word-level diff highlighting.

4

Copy & Share

Export the diff in standard format or share your comparison.

FAQ

Common questions

Everything you need to know about Diff Checker

We use a Longest Common Subsequence (LCS) based algorithm to detect differences. This approach intelligently identifies the minimum set of changes needed to transform one text into another, making it accurate for code, documents, and any text comparison.
Yes, absolutely. All comparisons are processed entirely in your browser. We never send, store, or log your data to any server. Your texts remain completely private and secure on your device.
Yes, you can compare large texts. However, very large files (10,000+ lines) may take longer to process. For optimal performance, we recommend comparing files under 50,000 lines. The comparison always happens in your browser without any size limits imposed by our servers.
When enabled, whitespace differences (spaces, tabs, line breaks) are ignored during comparison. This is useful for comparing code files where indentation or formatting may have changed but the actual content is the same.
After comparing, click the "Copy Diff" button below the results. This copies the diff in unified diff format (standard format used by git and other tools) to your clipboard, which you can paste anywhere.