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Text Compare — see every change

Paste two versions of a paragraph, email, or assignment and get an instant line-by-line diff, a quick similarity readout, and a copyable unified view. No upload — your text stays in this browser tab.

Trims and blank-line options rewrite the strings before the diff. “Ignore line leading/trailing spaces” is the diff engine’s per-line setting (good for indented code or poetry).

Line diff

Similarity

100%

Unchanged

0

lines

Removed

−0

in A

Added

+0

in B

Similarity is based on the line diff above (unchanged lines ÷ all line rows). It is a rough measure for drafts and code snippets — not a plagiarism score.

Add text in Text A and Text B to see a line-by-line diff. Everything runs in your browser — your content never leaves this tab.

Privacy

This diff uses JavaScript in your browser only. We do not upload your text to a server, log it, or store it. Safe for essays, policies, and API keys (still avoid pasting real secrets in any web page).

Finished comparing? Turn your best draft into a quiz.

Paste the text you like into the quiz generator and get multiple-choice, flashcards, and more in seconds. Free, no credit card.

Generate a quiz with QuizFlex AI

Frequently asked questions

Is this text compare tool free?
Yes. QuizFlex Text Compare is free to use, with no signup, no paywall, and no export limits. We display a short note about the QuizFlex app below the tool because building useful tools is how we connect teachers and students to our product.
Is my text uploaded to a server?
No. The comparison and diff are computed in your web browser with JavaScript. The text in Text A and Text B never leaves your device unless you copy it or navigate away, and it is not stored by us.
What does the similarity percentage mean?
It is a simple line-based ratio: the share of line rows in the diff that are unchanged, out of all changed and unchanged line rows. It is useful for quick drafts, policies, and notes — it is not a semantic similarity score and not a plagiarism detector.
What is a unified diff?
A unified diff lists lines with a + for additions (present in Text B), − for removals (only in Text A), and a space for unchanged lines, similar in spirit to the unified format used by version control. You can copy it for use in Changelog, email, or code review tools.
How do the ignore options work?
Trim, ignore blank lines, and ignore case rewrite the two strings in your browser before the diff. “Ignore line leading/trailing spaces” is applied inside the diff engine (like ignoring indentation differences) so small spacing changes do not count as new lines.
Can I compare long documents?
Yes for typical essays and code files. Very large pastes (hundreds of thousands of lines) can slow the tab because diffing is done in memory on your device. If it feels slow, work in smaller chunks or disable options you do not need.