Compare Two Texts Online
Original text
Changed text
Paste text in both boxes and click Compare
Text Tools
Paste two versions of any text and click Compare. Added lines are highlighted in green, removed lines in red, and unchanged lines are shown normally. The tool shows how many lines were added and removed so you can assess the scope of changes at a glance.
A diff checker compares two pieces of text and identifies what changed between them. The term "diff" comes from the Unix diff command, which has been a standard developer tool since the 1970s. Online diff tools make the same capability available to everyone — writers, editors, teachers, developers, and anyone who needs to track changes between two versions of a document.
Writers use a diff tool to compare a draft with a revised version or to check what an editor changed. Developers use it to review configuration file changes, compare API responses, or spot regressions in generated output. Students use it to check if their essay has been edited. Legal and compliance teams use it to track contract revisions. SEO professionals use it to check that a page's content changed as intended after an update.
This tool uses a longest common subsequence algorithm to identify the maximal set of lines shared between both texts. Lines in the changed text that are not part of the common sequence are marked as added; lines in the original text that are not part of it are marked as removed. Lines that appear in both are shown without highlighting.