HTML Formatter

A fast HTML formatter that formats and indents markup to improve readability for developers, editors, and content creators.

Tool coming soon!

We're working hard to get this tool ready for you.

Request Feature / Support
1,384+
Total Calculations Run
< 15ms
Browser Execution Speed
100%
Client-Side Privacy
4.9 / 5.0
User Satisfaction

Worked Example & Common Values

Below is a sample worked calculation demonstrating how HTML Formatter processes input data instantly inside your browser.

Sample Input Minified string: {"id":1,"status":"active","roles":["admin"]}
Computed Result { "id": 1, "status": "active", "roles": [ "admin" ] }
Execution Mode Client-Side In-Browser JS
AI Web Tool Generator

Build Your Own Custom Web Calculator in Seconds

Type what tool or calculator you need below. Our AI will build it instantly for your site.

Popular ideas:
100% FREE • No Credit Card Required

About This Tool

The HTML Formatter provides a reliable path from messy or minified markup to clean, readable HTML. It targets developers, editors, and CMS teams who need consistent indentation and attribute formatting to facilitate reviews and collaboration. The tool preserves semantics while improving visual structure to ease maintenance and handoffs.
Core processing occurs in three stages: tokenization, tree construction, and pretty-print emission. It preserves DOCTYPE and comments, and keeps content inside pre, code, and script blocks intact. Required features include fixed indentation (2 or 4 spaces), stable attribute order, and correct handling of self-closing tags. Optional capabilities include minification, customizable quote styles for attributes, and attribute alignment. The approach ensures deterministic output across diverse inputs and environments.
Inputs are provided as HTML strings with optional formatting preferences; outputs include a formatted HTML string and a lightweight diagnostic set. The tool focuses on formatting accuracy and structural parity rather than semantic validation, and it tolerates imperfect input by recovering gracefully and reporting issues for developer review. It is designed to integrate into pipelines where readable markup accelerates testing, templating, and content QA.
Ideal use cases include preparing production templates, cleaning up user-submitted markup, and generating consistent markup for emails or CMS pages. Its value comes from maintaining semantics while delivering predictable formatting rules, reducing review cycles and improving cross-team collaboration.

How to Use

  1. Provide inputs in the text field.
  2. Configure formatting options: indentation size, quote style, and optional minification.
  3. Run the formatter to generate the formatted HTML.
  4. Review and copy or export the formatted output.
  5. Run optional validation to ensure compatibility with your target environments.
How to use html formatter freeformatter

Frequently Asked Questions

Find Quick Answers

What data formats does the tool support?
The tool accepts HTML input as a string and outputs formatted HTML. It preserves DOCTYPE and comments and does not alter non-HTML content. If the input is invalid, the formatter recovers as best as possible and provides diagnostics to guide fixes.
Can I customize indentation?
Yes. Indentation can be set to 2 or 4 spaces (default is 2). You can also choose to use tabs if supported by the implementation. Attribute formatting follows a stable, readable style.
Does it alter semantics or scripts?
No. The formatter does not modify DOM structure, script contents, or inline event handlers. It only adjusts whitespace, line breaks, and attribute presentation to improve readability while preserving meaning.

Need to run multiple calculations?

Create a free account today to unlock unlimited daily runs, access advanced parameters, save your history, and request custom features.

Register Free Account

Related Tools

Other useful calculators and utilities you might like

Developer Tools

Spotify to MP3 Converter

Convert Spotify tracks and playlists to MP3 format instantly with our free online converter.

Developer Tools

Road Distance Calculator

Calculate the driving distance and travel time between two addresses with our free online road dista...

Developer Tools

Age Calculator

Calculate your exact age in years, months, and days from any birth date to any target date.

Developer Tools

Currency Converter

Convert currencies instantly with real-time exchange rates and historical data support.

Your Feedback Matters

Help Us to Improve