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Text Diff Checker

Compare original and modified text in your browser, with line or word differences and a readable summary.

What is Text Diff Checker?

A text diff checker compares original and modified text on your device and marks added, removed and unchanged lines or words.

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This tool runs in your browser. Inputs, files and generated values stay on this device. Favorites and recently used tools, if you use them, store only tool names in local storage — never passwords, documents or QR contents. See the privacy policy.

Text Diff Checker — Compare Two Texts Locally — Tools Star Hub

What this tool does

Paste an original and a revision and compare them by line or by word. Editors checking two drafts of the same paragraph use line mode for whole-line changes and word mode when a sentence was edited in place. Each side has to stay under 200,000 characters and under 4,000 lines or words.

How to use

  1. Paste the original text on the left and the modified text on the right.
  2. Choose line comparison or word comparison.
  3. Press Compare. Added, removed and unchanged blocks are labeled, not only colored.
  4. Copy the plain diff if you need it in another editor. Clear both sides when finished.

Examples

  • Two versions of a paragraph

    Line mode highlights whole lines that changed. Word mode is better when a sentence was edited in place.

  • Identical files

    If both sides match, the summary shows only unchanged content and no added or removed blocks.

How it works

The checker compares tokens in your browser. It does not send text anywhere and does not keep drafts in local storage. Differences are rendered as React text nodes, so user content cannot inject HTML. Very large inputs are rejected to keep the tab responsive.

Limitations

Each side must stay under 200,000 characters and under 4,000 lines or words, depending on the mode. The view labels added, removed, and unchanged blocks. It does not merge files, and it does not open a Word document.

See the disclaimer for what these tools do not cover.

FAQ

Is the Text Diff Checker free?
Yes. Comparing two texts line by line or word by word is free, and you do not need an account.
How do I compare two text files?
Paste each version into a panel, choose Lines or Words, then Compare. You can copy a +/- view of the result.
Is my input sent to a server?
No. Both panels are compared in this tab. The text is not sent to a server or saved in local storage.
What is a diff?
A diff is a list of the differences between two versions of a text: what was added, what was removed, and what stayed the same.
Should I use line mode or word mode?
Use line mode for code, lists, and files where whole lines change. Use word mode when a sentence was edited in place.

Related tools

Helpful guides

Guide

How to Clean and Compare Text

Remove duplicate lines, tidy whitespace, sort a list, and compare two drafts locally in the browser.

Read guide