Diff Checker
- Paste the original text into field A and the modified one into field B.
- Choose the comparison mode: by character, by word or by line.
- Differences appear highlighted, with a count of what was added, removed and kept.
- Use swap A and B to invert the sides and see the change in the opposite direction.
By line is the mode for reviewing code or a configuration file. It is the same granularity git uses, and it shows clearly when whole blocks have moved.
By word is best for prose. It isolates the changed word instead of marking the whole line, which is what makes reviewing a paragraph readable.
By character is the finest of the three. Use it to find the minimal difference between two similar strings: an accent, an extra space, a hyphen swapped for a dash.
When two lines look identical but the comparison flags a difference, switch to character mode: it is almost always trailing whitespace or an invisible character.
In character and word modes, the count is of characters. In line mode, it is of non-empty lines.
A changed line appears as one removal plus one addition, not as a single modification — that is how diff algorithms work in general, including git.
The comparison runs entirely in your browser. Neither text is sent to a server or logged.
That makes the tool suitable for comparing a contract, a report, a piece of proprietary code, or anything that should not pass through a third-party service.
Frequently asked questions
Almost always an invisible character: trailing whitespace, a tab instead of spaces, or a different line ending between Windows and Unix. Switch to character mode to locate it.
Line mode. That is the granularity git uses by default when showing changes.
The comparison runs in the browser and depends on available memory. Texts of a few thousand lines work fine; very large files in character mode can get slow, since the granularity is maximal.
Because the algorithm represents a change as a removal followed by an addition. There is no modify operation — this is true of virtually all comparison tools.
No. Everything is processed locally and nothing is stored.