Text Compare / Diff Checker
Compare two texts side by side with highlighted differences. Three diff modes, ignore options, unified view, and .diff download. Free. No sign-up. Runs in your browser.
How it works
- 1Paste or upload your texts
Paste the original text in the left panel and the modified version in the right panel. Upload .txt files directly if preferred.
- 2Choose your diff mode
Select line-by-line, word-by-word, or character-by-character comparison. Toggle options to ignore case, whitespace, or blank lines.
- 3Review and export
See differences highlighted in colour. Switch between side-by-side and unified views. Copy the diff output or download as a .diff file.
Why You Need a Text Diff Tool
Comparing two versions of a document, configuration file, or piece of code is one of the most common tasks in writing, editing, and development. Whether you are reviewing changes to a legal contract, checking edits to a blog post, or comparing two versions of a CSS stylesheet, a visual diff tool shows exactly what changed between versions.
This tool implements a longest common subsequence (LCS) algorithm to find the minimal set of changes between two texts. It works at three levels of granularity: whole-line diffs for a high-level overview, word-level diffs for prose editing, and character-level diffs for code review and debugging.
The side-by-side view with scroll synchronisation lets you see both texts at once, making it easy to understand additions, deletions, and modifications in context. The unified view condenses the diff into a single panel with +/- markers, following the standard unified diff format used by Git and other version control systems.
The ignore options are important for real-world comparisons. Ignoring case catches meaningful changes without flagging capitalisation differences. Ignoring whitespace removes noise from reformatted text. Ignoring blank lines focuses on content rather than formatting.
Common use cases include comparing document drafts before and after editing, reviewing code changes, checking translation accuracy between versions, auditing configuration file changes, and verifying that data migration preserved content correctly. All processing happens in your browser with no data sent to any server.