Text Diff Checker
Paste an original and a new version of a text to see every addition, removal, and change highlighted, line by line or character by character.
Differences
- Added
- 0
- Removed
- 0
- Changed
- 0
- Total changes
- 0
The two texts are identical.
How to compare two texts
Paste an original and a new version of a text to see every difference between them, highlighted line by line or character by character.
Line mode vs. character mode
Line mode compares whole lines, which is the natural choice for code, configuration files, or any text organized as separate lines: it shows exactly which lines were added, removed, or replaced.
Character mode compares individual characters and merges the result into readable runs, which works better for a sentence or short paragraph where you want to see a word or two change inside a single line.
Reading the highlighted result
Added content shows with a green background, removed content shows struck through with a light red background, and unchanged content is left plain. A line that was replaced is counted once as "changed", not once as a removal plus once as an addition.
How to use it
- Paste the original text on the left and the new version on the right, or drop a text file into either box.
- Switch between Line and Character mode depending on what you're comparing.
- Read the highlighted result and the added/removed/changed counts above it.
- Choose Copy to copy the highlighted result as plain text, with a leading + or - per line in Line mode.
Limits to know about
- Very large inputs (roughly a few thousand lines, or a similar number of characters in Character mode) are skipped with a message instead of freezing the page, since a full comparison grows quickly with size.
- The "changed" count is a helpful grouping, not a formal diff algorithm's output: it pairs up adjacent removed and added content in the same neighborhood, which matches how most edits actually look.
Local comparison
Both texts are compared entirely in your browser using JavaScript. Neither one is sent to a ProntoUso server, and files you drop are read locally with the File API.
Text diff checker FAQ
- What's the difference between line mode and character mode?
- Line mode treats each line as one unit, ideal for code or config files. Character mode compares individual characters, better for spotting a small edit inside a sentence or short paragraph.
- Why does it say the text is too large to compare?
- The comparison's cost grows with the size of both texts multiplied together, so very large inputs are skipped to avoid freezing the page. Try comparing a smaller section instead.
- Can I compare two files instead of pasting text?
- Yes. Drop a text file into the original or new text box; it's read locally and placed into that box exactly like pasted text.
- Is my text uploaded anywhere?
- No. The comparison runs locally in your browser, and nothing you paste or drop is sent anywhere.