QuickTooly

Free Text Diff Checker - Compare Two Texts Online

Instantly compare two texts and see exactly what changed. Our free text comparison tool highlights added and removed words, lines, or characters with a clean side-by-side view - no sign-up, no uploads, runs entirely in your browser.

Word diff, line diff & character diff - all free, all instant.

Paste your original and modified text below, choose a diff mode, and click Compare. Perfect for writers, editors, developers, and anyone who needs to track revisions, spot differences, or compare documents online between two versions of a file.

Diff mode:
Paste text into both panels and click Compare to see the diff.

Last updated: May 25 2026

Reviewed by the QuickTooly Team

Text Diff Guide

What Is a Text Diff Checker?

A text diff checker is an online tool that compares two versions of a document and highlights exactly what was added, removed, or left unchanged. It works the same way as the diff command used by developers - except it runs instantly in your browser with no installation required.

How to Compare Two Texts - 4 Steps

  1. 1. Paste the original text into the left panel labelled "Original".
  2. 2. Paste the modified text into the right panel labelled "Modified".
  3. 3. Choose a diff mode - Word for prose, Line for code, or Character for fine detail.
  4. 4. Click Compare - differences are highlighted instantly, with a summary of characters and chunks added or removed.

Why Use a Text Diff Tool?

  • Track changes instantly: See exactly what was added, removed, or kept between two versions of any document.
  • Three diff modes: Compare by word, line, or individual character depending on how granular you need to go.
  • Works for any text: Blog posts, contracts, code snippets, emails, translations - paste any plain text.
  • 100% private: Your text never leaves your browser. No server uploads, no data collection.
  • Completely free: No account, no paywall, no usage limits.

How Each Diff Mode Works - Word, Line & Character

Word Diff

Splits text by whitespace and compares word by word. Best for comparing prose, articles, or any text where sentence-level changes matter. Added words appear highlighted in green; removed words are struck through in red.

Line Diff

Compares text line by line, identical to how tools like git diff work. Best for code, CSV data, configuration files, or any structured text where line boundaries are meaningful.

Character Diff

The most granular mode - compares every single character. Useful for spotting typos, punctuation changes, or invisible whitespace differences that word diff would miss.

Tips for Comparing Text

  • Use Line mode for code: Line diff matches how version control systems work and makes structural changes easy to spot.
  • Use Word mode for prose: Word diff handles rewrites and edits more naturally than line mode for natural-language text.
  • Use Character mode for fine detail: Spot invisible differences like non-breaking spaces, smart quotes vs. straight quotes, or trailing whitespace.
  • Comparing JSON? For structured JSON data, try our JSON Compare tool which understands JSON structure and nesting.
  • Need to count words after editing? Use our Word Counter to measure the final length of your revised text.
  • Reformatting text? Our Case Converter lets you switch between uppercase, lowercase, title case, and more in one click.

Frequently Asked Questions

Is my text stored or sent to a server?

No. All comparison runs locally in your browser using JavaScript. Your text is never transmitted anywhere, stored in a database, or shared with any third party. You can safely paste confidential or sensitive documents.

Which diff mode should I use?

Use Word for general text and writing. Use Line for code, configuration, or structured data. Use Character when you suspect typos or hidden whitespace differences.

Can I compare code with this tool?

Yes - switch to Line mode for the best results with code. It shows exactly which lines were added or removed, matching the behaviour of tools like git diff. For JSON specifically, our JSON Compare tool provides structured, key-by-key comparison.

What do the colours mean?

Red strikethrough in the Original panel shows text that was removed. Green highlighted in the Modified panel shows text that was added. Unchanged text appears without any background colour.

Is there a text length limit?

There is no hard limit - everything runs in your browser. Very large texts (100,000+ characters) may take a second or two to process, but smaller documents compare instantly.

What is the difference between word diff and character diff?

Word diff splits text on whitespace and compares whole words - so changing "quick" to "fast" shows one removal and one addition. Character diff compares every individual letter, so the same change shows several removals and additions character by character. Word diff is easier to read for prose; character diff is best when you need to catch tiny changes like a missing hyphen or a smart quote.

Does the diff tool work on mobile?

Yes - the tool is fully responsive and works in any modern mobile browser. The side-by-side panels stack vertically on smaller screens for easier reading. Because everything runs in the browser, no app download is needed.

Can I diff PDF or Word documents?

This tool compares plain text only. To compare a PDF or Word file, first copy the text content from the document and paste it into the panels. For PDFs, most PDF readers let you select all text with Ctrl+A / Cmd+A and copy it to the clipboard.