Diff Checker - Compare Two Texts Online

Use this free diff checker to compare two blocks of text line by line. Paste your original and modified text to instantly see what was added, removed, or left unchanged — with options to ignore case and whitespace differences.

How does the Diff Checker work?

This tool splits both texts into lines and computes the longest common subsequence (LCS) between them — the same core algorithm used by tools like Git diff. Lines present in both texts are shown unchanged, lines only in the modified text are marked as additions, and lines only in the original are marked as removals.