Unicode-aware counts, reading time and platform limits
Text Diff Checker
Compare two texts and highlight additions and deletions by line, word or character with the Myers algorithm, ignoring whitespace and case, with a similarity score and a unified diff patch export.
Workspace
Differences
Unified diff
How the result is calculated
Each text is split into units (lines, words with whitespace, or characters) and the shortest edit script is computed with the Myers algorithm (O(ND)), which yields the fewest additions and deletions. Ignoring case and whitespace changes only the comparison key; the original text is displayed. Similarity = 2 × (matching units) ÷ (units of both texts), counted on words without whitespace in word mode. A unified patch with 3 lines of context is produced for line comparison.
Limits:
The limit is 200,000 characters for both texts together, and if the differences exceed 2000 units the texts are shown as a full replacement and the similarity is then approximate (0). The tool does not detect moved blocks and does not understand meaning: a reworded sentence appears as a deletion plus an addition. Character comparison on long texts is slow.
FAQ
What is the difference between line and word comparison?
By line each whole line is one unit, which suits code and lists. By word, changes inside a single line are shown, which suits prose.
Is my text sent to a server?
No, the comparison runs entirely in your browser.
