Text Diff Checker – Compare Two Texts Line by Line

A text diff checker compares two versions of a text and shows exactly which lines were added, removed or left unchanged.

Paste the original into the left box and the edited version into the right box, and the result appears at once: added lines get a green background and a + sign, removed lines get a red background, a - sign and a strikethrough, so the differences are readable even if you cannot tell red from green.

How does it find the differences? The tool uses a longest common subsequence method, the same idea behind version-control tools.

It finds the largest set of lines that appear in both texts in the same order and treats everything else as a change. Can it compare documents with different spacing? Yes.

Tick Ignore extra spaces to treat repeated spaces and trailing spaces as equal, and tick Ignore upper/lower case to treat Hello and hello as the same line.

For example, if the original has 3 lines and you insert one new line in the middle, the result shows 1 added line and 3 unchanged lines.

Because the comparison is line by line, a small edit inside a long line appears as one removed line and one added line, so compare line against line to find the exact word. Up to 3,000 lines can be compared at a time.

Everything runs in your browser and your text is never sent or saved. For counting words after you edit, try the Resume Character Counter or the Text Cleaner on this site.