Text Diff Checker
Compare two versions and see exactly what changed. Free, local and private—no account needed.
Compare in this tab. No text is sent or saved. Spaces and line breaks count as changes. Each field accepts up to 20,000 UTF-16 units: most characters use one, an astral emoji uses two. Long pastes are never cut. One side may be empty.
Enter text on either side to compare. One side may be empty.
How the comparison works
The checker compares words, punctuation and whitespace without changing either input. Added, Removed and Modified count separate change blocks, not words. Adjacent additions and removals form one Modified block; unchanged text separates blocks.
Calculation has a 100 ms time budget and a 1,000-edit work limit. If either is exceeded, no partial result is shown. Your texts stay intact so you can compare shorter passages. Editing either input clears the previous result.
Frequently asked questions
What do the added, removed and modified counts mean?
The comparison groups adjacent changes into blocks. A block only in the newer text is added; one only in the original is removed. A block containing both removed and added text is modified. These are block counts, not numbers of edited words or characters.
How precise is the comparison, and what are its limits?
It compares words and punctuation while preserving whitespace, with both panes retaining the exact text supplied. Each input has a length limit, and the comparison has time and edit-size limits. A large or very different pair may be refused; the tool reports that instead of showing a partial comparison.
Does comparing text rewrite or merge either version?
No. It displays differences without editing, merging or judging the quality of either version. Both texts stay in your browser. You decide which changes to use, and following a link to the rewriter does not send either input there.
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