Text Diff Checker
Compare two blocks of text and see every added and removed line highlighted.
Paste the original text on the left and the changed version on the right, then hit Compare. The checker runs a line-based longest-common-subsequence diff — the same idea behind version-control diffs — and shows a unified view with removed lines in red, added lines in green, and line numbers for both versions. Everything computes locally in your browser; neither document is uploaded.
Writers and editors use it to see exactly what changed between drafts, developers compare configs and code snippets without setting up git, and teams check contract or policy revisions line by line. Toggle ignore case or ignore whitespace to skip cosmetic differences, and copy the result as a classic unified diff with +/− prefixes.
How to compare two texts
- 1
Paste the original text into the left box and the changed text into the right box.
- 2
Optionally enable ignore case or ignore whitespace, then click Compare.
- 3
Review the highlighted unified view and copy the diff if you need to share it.
Why use Nofolo’s text diff checker?
Line-by-line LCS diff
A real longest-common-subsequence algorithm finds the minimal set of added and removed lines.
Unified view with line numbers
Green additions, red removals, and original/changed line numbers side by side — easy to scan.
Ignore case & whitespace
Optional toggles skip capitalization and spacing differences so only real changes show.
Change statistics
Instant counts of lines added, removed, and unchanged for a quick sense of the edit size.
Copy as unified diff
Export the comparison as plain text with +/− prefixes, ready for emails, tickets, or docs.
Private by design
Both texts stay on your device — nothing is transmitted, stored, or logged.
Frequently asked questions
How does the comparison work?
The tool computes the longest common subsequence (LCS) of the two texts’ lines using dynamic programming — the classic algorithm behind diff utilities. Lines only in the original are marked removed, lines only in the changed version are marked added, and everything else is unchanged.
Can it ignore capitalization or spacing differences?
Yes. Enable “Ignore case” to treat “Hello” and “hello” as identical, and “Ignore whitespace” to skip differences in indentation and repeated spaces. The displayed text is still your original — only the comparison is normalized.
Is there a size limit?
Each side is compared up to 3,000 lines to keep the diff instant in the browser. Longer texts are truncated to the first 3,000 lines and a notice is shown — for full novels, compare chapter by chapter.
Are my documents uploaded anywhere?
No. The diff is computed entirely in your browser with JavaScript. Both texts stay on your device, which makes the tool safe for contracts, unpublished drafts, and internal documents.
Can I export or share the result?
Yes — click “Copy diff” to get a unified text version where added lines start with “+”, removed lines with “−”, and unchanged lines with two spaces. It pastes cleanly into emails, chat, and issue trackers.
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