Text Diff Checker
Paste two versions of a text to see exactly which words were added, removed, or changed between them.
How the comparison works
The texts are split into words (keeping whitespace so line breaks and spacing are preserved), then compared using a longest-common-subsequence algorithm — the same technique behind tools like diff and Git's change tracking. It finds the longest run of words common to both texts and marks everything else as either removed (from the original) or added (in the new version), rather than just flagging lines as "different."
Common uses
- Reviewing exactly what changed between two drafts of an article or contract
- Checking what a co-author or editor modified in shared text
- Comparing two versions of code comments, documentation, or configuration text
Frequently asked questions
What's the difference between this and the Text Similarity Checker?
The Similarity Checker gives you a single percentage showing how much vocabulary two texts share. This Diff Checker shows you exactly which words were added, removed, or kept — useful when you need to see precisely what changed, not just how similar the texts are overall.
Does this compare line by line or word by word?
Word by word — this catches changes within a sentence (like a single word being swapped) that a line-level diff would miss, at the cost of being less useful for comparing code with meaningful line structure.
Can I use this to compare two versions of code?
It works on any text, including code, but since it's a word-level (not line-level) diff, it's better suited to prose than to code, where a dedicated code diff tool that understands line structure usually gives clearer results.
Is my text uploaded anywhere?
No — the comparison runs entirely in your browser using JavaScript. Neither text is sent to a server.