Text Compare
| Diff flavor | Best for | Example question |
|---|---|---|
| Line diff (this tool) | drafts, config, code | which paragraphs changed? |
| Word diff | prose polish | which word did the sentence gain? |
| Character diff | typos, digits | which single character differs? |
Paste one text on the left, another on the right, and the diff appears as you type: lines marked with a minus exist only in the left text, plus-marked lines exist only in the right, and unchanged lines carry through. The header keeps score - lines, words and characters on each side, plus how many lines were added and removed - so a revision can be described in one sentence: 12 lines added, 4 removed, everything else untouched.
Everything runs in your browser: the comparison happens on your device, nothing is uploaded to any server, and your two texts stay in this page's memory on your own machine for next time. The honest limit is 800 lines per side - the matching table that powers a line diff grows with the product of the two lengths, and past that this tool switches to counts-only rather than pretending. Code reviews, essay revisions, config changes and copy-paste sanity checks all fit comfortably inside it.
How to use
- Paste the original into the left box and the new version into the right - the diff and counts update as you type.
- Read the markers: minus lines were removed, plus lines were added, plain lines match in both.
- Copy the summary from the result line when you need to report the change size to someone else.
Frequently asked questions
How do I compare two pieces of text?
Paste the first version in the left box and the second in the right. The diff renders live - no button to press - and the result line counts it up: lines, words and characters on each side, then how many lines were added and removed between them. For long documents, compare the sections you actually changed rather than both full drafts; the 800-line cap is per side.
What do the plus and minus marks mean?
A line starting with a minus exists only in the left (original) text - it was removed. A line starting with a plus exists only in the right (new) text - it was added. Unchanged lines are shown plain so you can keep your place. Rewritten paragraphs show up as a minus block followed by a plus block, which is the diff way of saying 'these say different things now'.
Is my text uploaded anywhere?
No. The comparison runs entirely inside your browser tab - there is no server round-trip, no logging, no account. Your texts are also saved to your own device's local storage so they survive a page refresh, and they never leave your machine unless you personally copy and send them somewhere.
Why is there an 800-line limit?
A line diff works by matching every line of one text against every line of the other - a table with length-times-length cells. Two 800-line texts make a table of 640,000 cells, which is where this tool draws the line for smooth performance. Past the cap it still counts lines, words and characters so you can size the change; it just declines to guess the matching lines.
When should I use a line diff instead of a word diff?
Line diff is the right tool when edits happen in blocks: paragraphs rewritten, config lines changed, code functions replaced - it shows structure. A word diff suits prose polishing where a sentence gains one adverb and you want to see exactly which one; a character diff narrows further still, good for spotting a single wrong digit. This page does lines because that is where most real revisions live.