Suparank

Free Diff Checker

Compare two texts side by side and instantly see every difference with our free diff checker. Added text is highlighted in green, removed text in red, and modified sections are clearly marked. Perfect for code review, document comparison, and proofreading.

Free Diff CheckerInputOriginal: The quick brown fox | Modified: The quick red foxResultHighlight: 'brown' removed (red), 'red' added (green)
diff checker showing example with input "Original: The quick brown fox | Modified: The quick red fox" and result "Highlight: 'brown' removed (red), 'red' added (green)"

Diff Checker

Compare two texts line by line

How to Use This Diff Checker

  1. 1Paste your original text into the left input area.
  2. 2Paste your modified text into the right input area.
  3. 3Click the 'Compare' button to analyze the differences.
  4. 4Review the highlighted output showing additions, deletions, and unchanged text.

What Is a Diff Checker?

A diff checker is a tool that compares two versions of text and identifies exactly what has changed between them. The term diff comes from the Unix diff utility, which has been a standard tool in software development since the 1970s. Modern diff checkers use algorithms like the Longest Common Subsequence (LCS) to find the minimal set of changes needed to transform one text into another. Our diff checker presents results in a clear visual format with color coding, making it easy to spot additions, deletions, and modifications at a glance.

Tips for Using This Diff Checker

Use our diff checker for code reviews to see what changed in a file before committing. Writers and editors use it to compare draft versions of articles and documents. Legal professionals use diff tools to track changes in contracts. Students can compare their essay revisions to ensure they addressed feedback. For best results, make sure both texts are in the same format (plain text) before comparing. The tool works best with structured content like code, lists, and paragraphs rather than heavily formatted documents.

About This Tool

Diff tools are fundamental to modern software development, content creation, and document management. Every version control system from Git to Subversion relies on diff algorithms to track changes. Beyond code, diff checkers help lawyers review contract revisions, editors track manuscript changes, and quality assurance teams verify that updates only changed intended sections. Our browser-based diff checker brings this professional capability to everyone without requiring technical expertise or software installation. The color-coded output makes it immediately obvious what changed, saving hours of manual comparison.

Related Tools

Base64 Encoder

Encode and decode Base64

Hex to RGB

Convert hex colors to RGB

Barcode Generator

Create free barcodes

Reading Time Calculator

Estimate reading time

Frequently Asked Questions About Diff Checker

Yes, our diff checker is completely free with no usage limits or signup required.
Yes, our diff checker works great for code comparison. It handles syntax and indentation properly to show exactly what changed in your code.
No, all text comparison happens entirely in your browser. Your text is never sent to our servers, ensuring complete privacy.
You can compare texts up to approximately 50,000 characters each. For very large documents, consider breaking them into smaller sections.
Yes, you can copy the highlighted output or download it as a plain text file showing all changes clearly marked.
Our diff checker works with plain text. For Word documents or PDFs, copy and paste the text content into the tool after removing formatting.
We use a line-based diff algorithm that finds the longest common subsequence between texts, producing accurate and readable results.
Currently, our tool compares two texts at a time. For comparing multiple versions, run multiple pairwise comparisons.