Text Diff Checker
Compare two pieces of text and see what changed. Use it for edits, code snippets, email drafts, contracts, settings, product copy, or any text where small changes matter.
Text Diff Checker
Drop a text file here to load it.
Drop a text file here to load it.
Paste the original text on the left and the changed text on the right.
About this tool
Paste the old version on one side and the new version on the other. The tool marks lines that were added or removed, and inside changed lines it highlights the exact words that moved, so you don’t have to hunt by eye.
How to use it
- Paste the original text on the left and the changed text on the right, or drop a text file onto either box.
- Review the result. Green lines were added, red lines were removed, and highlighted words show what changed within a line.
- Use Ignore letter case or Ignore extra spaces to filter out noise, and Show only changes to skip long unchanged stretches.
- Copy or download the result as a unified diff, which most developer tools understand.
Common uses
- Review copy edits
- Check a revised policy
- Compare notes after a meeting
- Make sure a copied block didn’t lose a line
- Spot config changes between two environments
Tip: If every line shows as changed, the cause is often invisible: different line endings, trailing spaces, or tabs against spaces. Turn on Ignore extra spaces to check.
Privacy note
If the text is private or legally sensitive, remove names, IDs, and account details before comparing it. The comparison runs in your browser and your text is never uploaded.
Frequently asked questions
How does the comparison work?
It finds the longest run of lines that appear in both texts in the same order, a standard algorithm known as the longest common subsequence. Everything else is marked added or removed. Within a pair of changed lines it repeats the process on words.
Does it matter which side is which?
Yes. The left side is the original and the right side is the changed version, so “added” means present only on the right. Use Swap sides to flip them.
Is there a size limit?
Very large inputs are refused with a message, because comparing them in a browser tab would be slow. Most documents, scripts, and config files are far below the limit. For huge files, compare them in sections.
Can it compare files?
You can drop a plain-text file onto either box to load it. Binary files and Word documents are not supported; copy the text out first.