How to Compare Text and Find Differences
Finding what changed between two versions of a document, config file, or piece of code is a common task. Reading both versions and spotting differences manually is slow and unreliable — especially with long texts. A diff checker does it instantly and highlights every change.
How to compare text
- Paste both versions — enter the original text on the left and the modified text on the right.
- Review the highlights — added lines are shown in green, removed lines in red. Modified lines show both the old and new versions.
- Export or copy — copy the diff results or download a report.
Reading a diff
Diff output uses a simple color system:
- Green (added) — lines that exist in the new version but not the old
- Red (removed) — lines that existed in the old version but are gone from the new
- Unchanged — lines that are identical in both versions
This is the same convention used by Git, GitHub, and every major version control system.
When diff checking is useful
- Code review — compare your changes against the original before committing to see exactly what you modified
- Document revisions — find what changed between two versions of a contract, article, or policy
- Configuration debugging — compare a working config file against a broken one to spot the difference
- Data validation — check if two data exports are identical or find where they diverge
- Merge conflicts — understand both sides of a conflict before resolving it
Tips
- Paste clean text — remove headers, footers, or metadata that you do not want to compare. Extra noise makes real differences harder to spot.
- Use side-by-side view — seeing both versions next to each other with aligned line numbers makes differences easier to trace than an inline view.
- Check for whitespace — sometimes "identical" text has invisible differences like trailing spaces, different line endings (LF vs CRLF), or tabs vs spaces. The diff checker catches these.
- Works offline — once the page loads, comparisons run locally in your browser with no internet needed.
Frequently Asked Questions
Does the diff checker compare character by character?
It compares line by line, the same approach used by Git and most professional diff tools. If any character on a line changes, the entire line is highlighted as changed.
Is there a size limit?
There is no hard limit, but very large texts (over 10,000 lines) may take a moment to process since the comparison runs entirely in your browser.
Can I compare code files?
Yes. The diff checker works with any text, including source code. Syntax highlighting helps you read code diffs more easily.
Is my text sent to a server?
No. The comparison happens in your browser. Your text never leaves your device.