Text Compare
Paste two versions of a document and see exactly what changed — added, removed and unchanged lines highlighted side by side.
Line-by-line diff
Paste text into both boxes to see the differences highlighted here.
Quick answer
A text compare tool shows the differences between two blocks of text. Paste the original into the first box and the changed version into the second, and every line is flagged as added, removed or unchanged, with running totals. It uses a line-by-line diff and runs entirely in your browser, so your text stays private.
When to compare text
Spotting what changed between two versions is a constant need. Writers compare draftsto see an editor's revisions, developers compare code before committing, and teams compare contracts or policies to confirm exactly which clauses moved. Reading two documents side by side by eye is slow and easy to get wrong; a diff does it in an instant and never misses a line.
How the diff is calculated
The tool uses a longest common subsequencealgorithm, the same technique that powers version-control systems like Git. It finds the largest set of lines that appear, in order, in both documents — those are your unchanged lines. Everything left over in the original counts as removed, and everything new in the changed version counts as added. The result is a clean, ordered view of the edit rather than a jumble of mismatched lines.
Reading the results
Added lines are tinted green and prefixed with a plus sign; removed lines are tinted pink and prefixed with a minus; unchanged lines stay neutral. The counters at the top tell you how many lines were added and removed at a glance, which is useful for gauging the size of a change. Because the comparison is line based, keeping related content on its own line gives you the most precise diff.
Frequently asked questions
How does the text comparison work?+
The tool splits both blocks of text into lines and runs a longest common subsequence (LCS) diff — the same idea behind version-control tools. It then shows each line as unchanged, added or removed, and counts the additions and deletions for you.
What do the colours mean?+
Lines that exist only in the changed text are additions, tinted green and marked with a plus. Lines that exist only in the original are removals, tinted pink and marked with a minus. Lines that appear in both are unchanged and shown in plain text.
Does it compare word by word or line by line?+
It compares line by line, which is ideal for code, lists, configuration files and paragraphs separated by line breaks. If two lines differ by even one character, the tool treats the old line as removed and the new line as added.
Is there a size limit?+
There is no hard limit, but because the diff compares every line against every other line, very large documents of many thousands of lines will take longer. For typical documents, code files and lists it is instant.
Is my text kept private?+
Yes. The comparison happens entirely in your browser with JavaScript. Neither block of text is uploaded or stored, so it is safe for confidential drafts, contracts and source code.