99 · Text Tools

Text Diff Checker

Paste the original and the changed text to see exactly what was added, removed or reworded.

How to use the text diff checker

  1. Paste the original text on the left.
  2. Paste the new version on the right.
  3. Read the highlighted differences below, or copy them as a unified diff.

How the comparison works

The checker finds the longest run of lines the two texts share and marks everything else as added or removed. When a line was edited rather than replaced, the changed words inside it are highlighted, so a single typo fix doesn’t look like a rewrite.

Examples

“quick brown fox” → “quick red fox”

1 line changed; “brown” and “red” highlighted

Ignore case on: “Hello” vs “hello”

No differences

Questions

How long can the texts be?

Several thousand lines each compare instantly. Very large, very different files may be too slow, and you’ll see a message.

Is my data uploaded?

No. Everything runs in your browser, so what you paste never leaves your device.