What does an HTML formatter do?

An HTML formatter (also called a beautifier) reformats messy or minified HTML with proper indentation, line breaks between tags, and consistent attribute formatting. The output is functionally identical but far more readable for editing and code review.

Will formatting break my page rendering?

No for normal markup. HTML treats whitespace between block tags as insignificant. The exception: whitespace inside , , , or with explicit white-space CSS is preserved — Prettier respects this. Inline elements (span, a) may show different spacing if you reformat them across lines.

What indentation should I use for HTML?

2-space indentation is the most common standard (used by Google's HTML/CSS style guide, MDN, and most React/Vue projects). 4-space matches some Microsoft conventions. Tab indentation suits accessibility (users can choose their visual indent width). Pick one and apply consistently.

Is this different from an HTML minifier?

Opposite directions. The formatter adds whitespace for human readability — used in source files. The minifier strips whitespace for production delivery — smaller file, faster load. Format your source, minify before shipping.

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HTML Formatter

Format

Beautify and format HTML. Clean up messy or minified markup with proper indentation.

Input

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Output

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✨ AI Code Explanation

Mode

What is an HTML Formatter?

An HTML formatter (also called an HTML beautifier) automatically reformats your markup into clean, consistently indented code — making messy or minified HTML easy to read and maintain. It is powered by Prettier running entirely in your browser.

How to Format HTML Online

Paste HTML into the Input pane, or click Upload to load a file.
Choose 2, 4, or 6 space indentation — the output updates when you click Format.
Enable ⚡ Live to auto-format as you type (400 ms debounce).
Enable Auto-comment to inject section labels above structural blocks.
Click Format to beautify your HTML.
Use Copy or Download to save as formatted.html.
Click Explain with AI for a plain-English breakdown of the HTML structure.

Auto-Comment — What Does It Do?

When Auto-comment is enabled, the formatter scans your HTML after beautifying and inserts descriptive comments above major structural elements like <header>, <nav>, <main>, <footer>, and <div> blocks with meaningful id or class names (e.g. class="sidebar" becomes ).

Indentation Guide

2 spaces — the most common convention; used by Google, Airbnb, and most style guides.
4 spaces — preferred by Microsoft, Bootstrap, and many legacy projects.
6 spaces — occasionally used for deeply nested templating systems.

HTML Formatter vs. HTML Minifier

Formatting expands HTML for human readability during development. HTML Minification does the opposite — it strips all whitespace for the smallest possible production file. Use the formatter in dev; minify before deploy.

Common Errors

Void elements with content — <br>, <img>, <input> cannot have children. Prettier will flag these.
Unclosed tags — missing </div> or </p> causes unexpected nesting in the formatted output.
Inline JS/CSS — Prettier also formats embedded <script> and <style> blocks.

Keyboard Shortcuts

Ctrl + / — Toggle HTML comment on selected line
Tab / Shift+Tab — Indent / dedent selection
Ctrl + Z — Undo · Ctrl + Y — Redo

Related Tools

HTML Minifier — compress HTML for production
HTML Validator — validate HTML against W3C standards
CSS Formatter — beautify CSS stylesheets
JavaScript Formatter — format JS with Prettier

Is My Code Sent to a Server?

No — formatting runs entirely in your browser using Prettier. Your code never leaves your machine.