Text Diff Checker

See Free Text Diff Checker & Comparison Tool in action

azrscorp.com/quickfix/diff-checker/

1Paste the original text into the first box and the revised version into the second.

2Choose Line mode or Word mode depending on what you're comparing.

3Toggle Ignore Whitespace or Ignore Case if formatting shouldn't count as a change.

Free Text Diff Checker & Comparison Tool

Paste two versions of a text — two drafts, two code snippets, or two config files — and see exactly what changed between them. Choose Line mode to compare whole lines at once (best for code and config files) or Word mode to see which individual words within a changed line were added or removed (best for prose editing).

The result includes a similarity percentage based on the ratio of unchanged to total lines, plus toggles to ignore whitespace differences or case differences when you only care about substantive content changes, not formatting.

Key features

How to use it

1. Paste the original text into the first box and the revised version into the second.
2. Choose Line mode or Word mode depending on what you're comparing.
3. Toggle Ignore Whitespace or Ignore Case if formatting shouldn't count as a change.
4. Run the comparison and review the highlighted differences and similarity score.

Worked example

Example

Text 1: "The quick brown fox jumps."
Text 2: "The quick red fox jumped."
Word diff highlights: "brown" removed, "red" added; "jumps" removed, "jumped" added. Similarity: 60%.

Who uses this tool

Tips for the best results

• Use Word mode for prose editing — Line mode will mark a whole sentence changed even if only one word differs.
• Enable Ignore Whitespace when comparing code with different indentation styles but identical logic.
• The similarity percentage is a quick health check, not a precise metric — always read the highlighted diff for real detail.
• For very long documents, compare section by section for a more readable diff output.

Common mistakes to avoid

• Using Line mode on prose and assuming a highlighted line means the entire sentence is new — check the actual wording change.
• Forgetting to enable Ignore Case when comparing text that only differs in capitalization, inflating the perceived number of changes.
• Pasting text with inconsistent line endings (Windows vs Unix) without ignoring whitespace, which can show false line-level differences.

Frequently asked questions