Text and File Diff Checker

Text and File Diff Checker

Compare two texts or local text files line by line, marking additions, removals and unchanged lines.

Comparison is case- and whitespace-sensitive; LF and CRLF separate lines. Added lines use +, removed lines use − (U+2212). Limits per side: 500,000 UTF-16 code units, 20,000 lines and 5 MiB per file. The additional matrix limit is (left lines + 1) × (right lines + 1) ≤ 4,000,000, so individual maxima cannot be combined.

Text files are decoded as UTF-8, so other encodings may display incorrect characters. The editors normalize CRLF and lone CR to LF.

Comparison uses line-level LCS. Replacements appear as added and removed lines, not a dedicated replacement row. There is no word- or character-level diff view, ignore-whitespace option or merge editor. Reading and comparison run in this browser; this tool does not upload the contents.

A: red
B: blue

+ blue
− red