Text Diff Checker
Compare two blocks of text online for free and see line-by-line additions and removals. No signup, nothing uploaded — runs entirely in your browser.
Your files are processed locally in your browser and are not uploaded to our servers.
How to use Text Diff Checker
- 1
Paste the original text on the left and the changed version on the right.
- 2
Differences are highlighted line by line as you type — green for added lines, red for removed lines.
- 3
The count of added and removed lines is shown above the comparison.
Common uses
- Checking exactly what changed between two drafts of an email, contract, or article
- Reviewing edits made to a config file or exported text before applying them
- Comparing two versions of a list to see what was added or removed
Supported formats and limitations
Accepts text, up to one file at a time.
- Comparison is line-by-line, not word-by-word within a line — a line with even a single character changed shows as one removed line and one added line.
- Extremely large inputs (millions of line-pairs) fall back to a simplified diff rather than freezing the browser on the exact comparison algorithm.
Frequently asked questions
No. Comparison happens entirely in your browser.
Line-by-line — a line is shown as changed (removed + added) if anything within it differs, down to a single character.
No hard limit, but very large inputs (many thousands of lines on both sides) fall back to a simplified diff to keep the browser responsive.
Yes — plain text is plain text; it works on code, config files, or any other line-based content.