← Back to all tools

TOOL · 56 · Data & Utility

Text Diff Checker

Compare two blocks of text and see additions, removals and unchanged lines side-by-side.

In short
Text Diff Checker compares two blocks of text line-by-line and highlights additions, removals and unchanged lines — a fast side-by-side diff that runs entirely in your browser.

Processed 100% in your browser — your files never leave your device.

+2 added−2 removed1 unchanged
−The quick brown fox
+The quick red fox
jumps over the lazy dog.
−End.
+Goodbye.

How it works

  1. Step · 01

    Paste the original text on the left and the changed version on the right.

  2. Step · 02

    Added lines appear in green, removed lines in red, unchanged in gray.

  3. Step · 03

    Diff runs entirely in your browser — nothing is transmitted.

Related tools

Frequently asked questions

Is this a word-level or line-level diff?
Line-level. Two lines that differ by even one character are shown as one removal and one addition.
Is there a size limit?
No hard limit, but very large inputs (tens of thousands of lines on both sides) may slow down the browser because it uses an exact LCS diff.
Are my files uploaded to a server?
No. Files are processed directly in your browser using JavaScript and WebAssembly. Nothing is uploaded to our servers, so your documents never leave your device.
Does it work on mobile?
Yes. The tools run in any modern browser on desktop, tablet, or mobile (Chrome, Edge, Safari, Firefox). Very large files may be slower on low-end phones.