How to compare two texts
- Paste the original into the left box and the changed version into the right.
- Optionally tick Ignore whitespace differences.
- Click Compare. Removed lines appear in red with a −, added lines in green with a +, and line numbers from both versions are shown in the margins.
Click Edit texts to go back and adjust.
Reading the output
| Marker | Meaning |
|---|---|
| (none) | Line is in both texts |
− red |
Line is only in the original |
+ green |
Line is only in the changed text |
A modified line shows as a removal followed by an addition — the tool compares whole lines, which is the convention for code and documents and keeps the display simple.
Common uses
- Reviewing edits — see exactly what a colleague changed in a document or contract.
- Debugging config — compare a working and a broken configuration file to find the one line that differs.
- Checking generated output — did the new version of a script produce the same result?
- Comparing versions — two exports of the same data, two drafts of an email, two API responses.
- Plagiarism and duplication checks — quick comparison of two passages.
Tips
- Normalise first if you can: sort lists, format JSON with the JSON formatter, or strip timestamps, so the diff shows real differences rather than noise.
- Whitespace mode is your friend for code copied from a web page or chat, where indentation often gets mangled.
- Long lines are shown wrapped; the diff is still line-based, so a single changed word in a long paragraph marks the whole paragraph. Break text into shorter lines (one sentence per line) for finer results.
- Ordering matters. Moving a block of lines shows as a removal in one place and an addition in another, not as a “move”.
Frequently asked questions
How does the comparison work?
It finds the longest sequence of lines common to both texts and marks everything else as removed (red, −) or added (green, +). This is the same approach used by Git and the Unix diff command.
Can I compare files?
Paste their contents. For binary or very large files (over a few thousand lines each), use a desktop diff tool — browser memory is the limit.
What does "ignore whitespace" do?
Lines that differ only in spaces, tabs or trailing whitespace are treated as identical. Useful for code that was re-indented or text with inconsistent spacing.
Is my text uploaded?
No. The comparison runs in your browser. Contracts, code and drafts stay on your device.
Last updated August 26, 2026.