Text Compare & Diff Checker
Paste two versions and see exactly what changed, down to the word, without uploading either one.
In short
Word-level comparison suits prose, where a single changed word should show as one change rather than a rewritten paragraph. Line-level suits code and structured data, where the line is the meaningful unit.
Last reviewed
Runs entirely in your browser. Nothing you type here is uploaded, stored or logged.
Word mode versus line mode
Word mode is what you want for prose. Change one word in a paragraph and you see exactly that word marked, with everything around it intact. Line mode would report the entire paragraph as removed and a new one added, which tells you almost nothing.
Line mode is better for structured content, code, CSV rows, lists, configuration files. Where a line is the meaningful unit and you care which lines moved rather than which words.
A useful habit: start in word mode to see what actually changed, then switch to line mode if the document is long and you need to locate the changes rather than read them.
What the highlighting means
- Green: present in the changed version but not the original. Added.
- Red with a strikethrough: present in the original but not the changed version. Removed.
- Plain: identical in both.
A rewritten sentence appears as the old version struck through immediately followed by the new one. That is correct behaviour rather than a limitation. A diff has no way to know that two different sentences were "the same sentence, edited".
The ignore options
Ignore whitespace collapses runs of spaces and tabs so that reformatting doesn't drown out real changes. Essential when the two versions came from different editors, or when one has been through a word processor that reflowed everything.
Ignore case treats "The" and "the" as identical. Useful when comparing text where capitalisation has been normalised, and worth turning off again before a final check, since case sometimes matters.
Where a diff earns its keep
- Contract revisions. Find what the other side actually changed rather than trusting a summary email.
- Essay and article drafts. See what an editor or collaborator altered.
- Terms and policies. Compare an archived version against the current one.
- Translations and localisation. Check which source strings moved.
- Copy review. Confirm that requested edits were actually applied, and nothing else was.
- Data exports. Spot which rows differ between two extracts.
What a diff cannot tell you
It shows what changed, not what the change means. Deleting the word "not" is one tiny red mark and can reverse the meaning of a clause entirely. A diff is a tool for directing attention, not a substitute for reading the parts it points at.
It also can't recognise moved content. A paragraph relocated from the top of a document to the bottom shows as a deletion in one place and an addition in another, rather than as a move.
Nothing is uploaded
The comparison runs in your browser. That matters here more than for most tools, because the documents people most need to diff, contracts, settlements, unreleased copy, exported customer data. Are exactly the ones you should not be pasting into a service that sends them to a server.
Frequently asked questions
How do I compare two documents?
Paste the original on the left and the revised version on the right. Differences are highlighted immediately, removed content in red, added content in green. Switch between line and word view depending on how fine-grained you need it.
What is the difference between line and word mode?
Line mode compares whole lines, which suits code, lists and anything structured. Word mode compares individual words, which is far more useful for prose. Changing one word in a paragraph shows as one word changed rather than the whole paragraph being replaced.
Can it ignore formatting differences?
Yes. "Ignore whitespace" treats runs of spaces and tabs as equivalent, and "ignore case" treats upper and lower case as the same. Both are useful when comparing text that has passed through different editors and picked up cosmetic changes.
Is this good for checking contract revisions?
It is genuinely useful for spotting what moved between drafts, and nothing is uploaded so it is safe for confidential documents. It is not a substitute for a lawyer reading the final version. A diff shows what changed, not what the change means.
Is my text sent anywhere?
No. The comparison runs entirely in your browser, which is the main reason to use this rather than a service that uploads both documents to a server.