Text Diff Checker

About this tool

Paste two versions of a text, a config file or a piece of code and see exactly which lines were added, removed or changed. Inside a changed line, the words that differ are highlighted too.

Everything runs in your browser. Neither text is sent to a server.

How it works

• The comparison is line by line and finds a longest common subsequence of lines, so moved blocks show up as a removal and an addition.
• Ignore whitespace treats runs of spaces and tabs as one space and ignores leading and trailing spaces. Ignore case compares lines in lower case. The text shown is always your original.
• Line endings (Windows CRLF and Unix LF) are treated as the same, so a file saved on another system does not show every line as changed.
• Copy as unified diff produces the standard format with three lines of context (@@ -1,4 +1,5 @@) that git apply and patch understand. It marks a missing final line break with \ No newline at end of file. With Ignore whitespace or Ignore case ticked, lines that differ only in those ways are shown as unchanged in the copied diff, so it will not reproduce your second text exactly. It has no file header, so add --- and +++ lines if the tool you use needs them.
• To keep the page responsive, very large changes are refused: after removing identical lines at the start and end, the product of the remaining line counts must stay under 25 million (about 5,000 changed lines on each side).

FAQ