How to use the Text Diff Checker tool
- Paste the originalPut the first version of your text, document or code in the left box.
- Paste the changed versionPut the new version in the right box.
- CompareClick “Compare texts”. Removed parts are red, added parts are green, and edited words are highlighted inside changed lines.
- Refine the viewSwitch between side-by-side and unified views, ignore case or spacing, or show only the changes.
Features
- Accurate diffUses the Myers algorithm, the same approach as Git, to find the smallest set of changes.
- Word-level highlightingSee exactly which words changed in a line instead of hunting for them.
- Two viewsSide by side for reading, unified for a compact Git-style overview.
- Ignore optionsSkip differences in letter case or extra spaces when they don’t matter.
- PrivateThe comparison runs in your browser. Your text is never uploaded or stored.
What is a diff checker?
A diff checker compares two pieces of text and shows the differences between them. Instead of reading two long documents line by line, you see at a glance what was added, removed or changed. The name comes from the classic Unix diff command, which programmers have used for decades to compare files.
Common uses
- Contracts and agreements: check exactly what the other side changed in a new draft before signing.
- Writing and editing: compare essay drafts, articles or translations, and review an editor’s changes.
- Code and configuration: find the line that differs between two config files, SQL queries or code snippets.
- Data and lists: spot missing or extra entries between two exports or lists of names, emails or IDs.
- SEO and content: see what a competitor or colleague changed on a web page.
How to read the results
| Mark | Meaning |
|---|---|
| − red line | Removed: exists only in the original text |
| + green line | Added: exists only in the changed text |
| Red and green on the same row | Changed: the line was edited; the exact words are highlighted |
| No color | Unchanged |
Tips for better comparisons
- Comparisons are line by line. If one version is a single long paragraph and the other has line breaks, break both into sentences or paragraphs first.
- Use Ignore extra spaces when comparing text copied from PDFs or web pages, where spacing often differs.
- Turn on Show changes only for long documents: unchanged sections are collapsed, with three lines of context around each change.
- To clean up lists before comparing, try Remove Duplicate Lines or the Case Converter.
Frequently asked questions
How do I compare two texts for differences?+
Paste the original text on the left and the new version on the right, then click “Compare texts”. Differences are highlighted immediately.
Is my text uploaded or saved?+
No. The comparison runs entirely in your browser, so confidential documents and code stay on your device.
Can I compare code with this tool?+
Yes. It works with any plain text, including code, JSON, CSV, HTML and configuration files.
Can it ignore uppercase/lowercase differences?+
Yes. Tick “Ignore case”. You can also tick “Ignore extra spaces” to skip spacing differences.
How long can the texts be?+
Up to 20,000 lines per side. Typical documents compare in a fraction of a second.