Diff Checker - Free Online Text Comparison Tool (Side-by-Side)

How to Use This Free Side-by-Side Comparison Tool

Paste the original text into the left panel and the modified text into the right panel.
Differences are highlighted automatically - additions in green, deletions in red.
Switch between line-level and word-level diff modes for different granularity.
Use the line jump arrows to navigate between changed sections in long documents.

Diff Checker provides a fast way to compare two pieces of text online and find differences instantly. It is the same comparison operation used by Git, code review tools, and file merge utilities - but accessible directly in the browser without any setup, for any text content: code, documents, configuration files, or prose.

Line Diff vs Word Diff vs Character Diff

Line diff shows which entire lines were added, removed, or changed - the standard Git diff view. Word diff highlights individual changed words within each line, making it easier to spot edits in prose. Character diff highlights individual character changes - useful for catching small typos or formatting differences. This tool supports all three modes.

Line-level, word-level, and character-level comparison modes
Unified diff view (like Git) and split/side-by-side view
Changed line count and statistics summary
Download the diff as a unified diff file

Frequently Asked Questions

What is a unified diff format?

A standard text diff format with context lines and change markers: lines starting with + were added, lines starting with - were removed, and unmarked lines are context (unchanged). This format is read by patch utilities and code review systems.

Can I compare binary files?

No - this tool compares text files (string content). Binary files should be compared with binary diff tools like xxd or hex editors.

Does it handle different line endings (CRLF vs LF)?

Yes - enable "Normalise line endings" to strip carriage returns before comparing. This prevents Windows CRLF files from appearing entirely changed when compared to Unix LF files.

Can I compare minified JavaScript or CSS files?

Yes, but minified single-line files will show the entire line as changed if anything differs. Use the CSS Prettifier or a JS formatter on both files first, then compare the formatted versions for a readable diff.

Whether you are comparing source code or reviewing document versions, this browser-based utility is your go-to Diff Checker.

Diff Checker side-by-side online

Compare two texts side by side and highlight the differences