Compare two texts and highlight differences.
The Text Diff Checker compares two versions of a text line by line and shows what changed. Lines that appear only in the changed text are marked with a plus and shaded green, and lines that appear only in the original are marked with a minus and shaded red. The comparison follows the order of the text, so inserting one line does not mark everything below it as changed. You can ignore case and extra spaces, try a built-in example, and copy the result as a plus-and-minus diff. Both texts stay in your browser.
Made for writers and students. Typical uses:
Comparing a four-line original with a five-line version in which "lazy dog" became "sleepy dog" and a new line was added shows one removed line, two added lines and three unchanged lines: the changed sentence appears once in red and once in green, the new line in green, and the rest in plain text.
The comparison works on whole lines. If one word in a long paragraph changes, the entire line shows as removed and added, and the exact word is not highlighted. It does not understand file formats; for JSON use a comparison that works by key.
Accuracy: Results follow documented rules and are tested with known inputs. Review the output before relying on it.
Expert Tip
Put each sentence or item on its own line before comparing. Short lines make the diff precise, and the ignore-spaces option stops reformatting from hiding the edits that matter.
A diff compares two versions of a text and shows exactly what changed. The Text Diff Checker compares line by line and follows the order of the text, so inserting a line does not mark everything below it as changed. Lines that only exist in the changed text are marked with a plus and shaded green, and lines that only exist in the original are marked with a minus and shaded red.
Here is the tool's own example. The original has four lines and the changed text has five:
Paste the original into the left box and the changed version into the right box, then press Compare. The summary counts the lines added and removed, or tells you the two texts are identical. A Copy diff button gives you the result in the plus-and-minus format that code reviewers and version control tools use.
Two options help when the differences are noise. Ignore case treats Hello and hello as the same, and Ignore extra spaces collapses runs of spaces and trims each line before comparing, so reformatting does not hide real edits. The tool still shows your original text, not the normalised version.
Line-based comparison suits text where the line is the natural unit.
The comparison works on whole lines. If one word in a long paragraph changes, the whole line appears as removed and added, and the tool does not highlight the single word. For structured data, use a comparison that understands the format: the JSON Diff Checker compares objects by key. For checking that a list has no repeated entries, the Duplicate Line Remover is faster, and to see how much longer one draft is than another, the Word Counter gives the totals.
Both texts stay in your browser, so private drafts are safe to paste.
The Copy diff button produces text in a plus-and-minus layout similar to the one used by version control tools: a line starting with a plus was added, a line starting with a minus was removed and a line starting with a space is unchanged. You can paste it into an email, a ticket or a code review comment so that others see exactly what changed without opening both files. When a document has been reformatted, tick the ignore options first, so the diff shows edits to the words and not the spacing.
Explore more in Text Tools, read the guides and articles, or see how we test our tools.
Compare two JSON objects side by side.
Best for comparing two versions of an API response to spot what changed
Remove duplicate lines from any text instantly.
Best for cleaning a merged email or contact list
Count words, characters, sentences, and paragraphs in any text.
Best for checking word count for essays, articles, and blog posts
Sort text lines alphabetically (A-Z or Z-A).
Best for alphabetizing a contact list or spreadsheet column before import
Remove extra whitespace, tabs, and line breaks from text.
Best for fixing double spaces left by typing or by pasting from a layout