Text Compare (Diff Checker)

What Is Text Compare?

Text Compare, also called a diff checker, shows exactly what changed between two versions of a text. Added parts are highlighted in green and removed parts in red with a line through them. You can compare by line, by word or by character, and ignore differences in capital letters or spacing.

When to Use It

• Checking what an editor or a colleague changed in a document.
• Comparing two versions of a contract, policy or terms page.
• Finding the difference between two configuration files or code snippets.
• Spotting a single changed digit in two long lists of numbers.

How to Use It

1. Paste the original text on the left and the changed text on the right.
2. Choose Line, Word or Character.
3. Click Compare. Use Swap to compare the other way round.

Example

Comparing two versions of an office notice by word shows that Friday, became Saturday,, 5pm. became 6pm. and the word all was added before visitors. The summary reads +3 words added, -2 words removed, and the unchanged phone number line is shown without highlighting.

Choosing Line, Word or Character

Line mode is best for code, lists and configuration files, where each line is a unit. Word mode suits prose: a changed word is highlighted without marking the whole sentence. Character mode finds the smallest changes, such as a swapped digit or a missing comma. The comparison uses the Myers difference algorithm, the same approach behind git diff, so it shows the smallest set of changes.

Limitations

If a paragraph was moved, it appears as removed in one place and added in another. Very long texts that are almost completely different are better compared by line. The comparison runs in your browser, so nothing you paste is uploaded. To measure how similar two texts are as a percentage, use the Text Similarity Checker; to read a Git patch, use the Git Diff Viewer.