Compare Two Blocks of Text Line by Line
Spot every difference between two blocks of text, line by line.
Both texts are compared in your browser — nothing is sent to a server.
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About comparing text
Spotting exactly what changed between two versions of a document, a paragraph, or a piece of code by reading them side by side is slow and error-prone — the kind of task a diff tool does instantly and reliably. This tool compares two blocks of text and highlights every difference, line by line.
It runs a text-diffing algorithm directly in your browser's JavaScript, aligning the two inputs and marking additions, deletions and unchanged lines with color so the differences jump out visually rather than requiring you to read both versions in full.
Supported files
No file — paste two blocks of text. Produces a line-by-line, color-coded diff on screen.
Is my file uploaded?
Yes, completely private. Both texts are compared entirely in your browser and are never sent anywhere.
How to Compare Text
- 1
Paste both versions
Put the original text on the left and the changed text on the right.
- 2
Compare
Click Compare — added lines are green, removed lines are red.
- 3
Review
Scroll the line-by-line diff to see exactly what changed.
Compare Text — frequently asked questions
Does it compare word by word or line by line?+
Line by line, using a longest-common-subsequence diff — the same approach code review tools use.
Is there a size limit?+
It handles typical documents easily. Very large inputs (tens of thousands of lines) may be slow because the diff is computed in your browser.
Is my text uploaded?+
No. Both versions are compared locally and never sent anywhere.
Is there a free way to compare two texts and find the difference?+
Yes — this tool diffs the two texts entirely in your browser, free and with nothing uploaded.
Do you upload my files to a server?+
No — every tool here processes your files entirely on your device, and nothing is uploaded to a server. The only exception is the AI tools, which send the extracted text (not the file) to Claude to do their work.
Is there a file size limit?+
There's no artificial limit we impose, but since processing happens in your browser, very large files (500+ MB or 1,000+ pages) are limited by your device's memory rather than by us.
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