Diff Checker
Compare two texts online free and highlight every difference by line, word or character. Free online diff checker with ignore case and whitespace options.
Processed locally in your browserHow?
This tool runs in this browser tab. The files, text and values you enter are not uploaded to clkr.work servers — closing the tab clears them. Anonymous usage events (such as which button was pressed) are counted, never your content. Privacy policy
What next?
Found it useful? Share Diff Checker
Free, no sign-up, works in the browser — send it to a friend or add it to your site.
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Part of these toolkits
How to use Diff Checker
- 1Paste the original text on the left and the changed version on the right
- 2Choose to compare by lines (code, lists), words (documents) or characters (short strings), and optionally ignore case or whitespace
- 3Click Compare: additions are green, deletions are red and struck through; copy the diff to share it
Frequently asked questions
How does the diff checker work?▾
It uses the Myers diff algorithm — the same approach as git diff — to find the smallest set of insertions and deletions that turns the original text into the changed one.
Should I compare by lines, words or characters?▾
Lines work best for code, CSV and lists. Words are best for articles, contracts and essays. Characters are useful for short strings like IDs or passwords where a single letter matters.
Can I ignore spacing or capitalization differences?▾
Yes. Tick Ignore whitespace to treat runs of spaces and tabs as equal, and Ignore case to treat upper and lower case as the same.
Is my text uploaded?▾
No. The comparison runs entirely in your browser, so confidential documents and code never leave your device.
Embed Diff Checker on your website▾
Paste this snippet into your page. The embedded tool runs in your visitor's browser and shows a small “Powered by clkr.work” link.