Format HTML Online Free — Auto-Indent and Beautify HTML Code
Table of Contents
HTML that was pasted, exported, or auto-generated is usually a mess — collapsed to one line, inconsistently indented, or missing readable structure. Manually fixing indentation in HTML is tedious and error-prone. An online formatter handles it in seconds.
This page covers how to clean up HTML code online using our free browser-based HTML formatter, what it does and doesn't fix, and practical situations where you'll reach for it.
What the HTML Formatter Fixes
The formatter uses the Prettier HTML parser to restructure your markup. It handles:
- Indentation — every nested element gets properly indented, consistently, at 2 or 4 spaces
- Attribute formatting — attributes are formatted on one line or multiple lines based on print width
- Self-closing tags — void elements like
<img>and<input>are handled correctly - Inline vs block elements — Prettier knows which elements are inline (span, a) vs block (div, p) and formats accordingly
- Long line wrapping — elements wider than your print width setting are broken across lines
- Template syntax — works with plain HTML, not templating languages like Jinja or Handlebars
It does NOT change your HTML's structure, remove elements, or validate against HTML5 spec. It only reformats for readability.
Common Use Cases for HTML Formatting
The most common reason to reach for an HTML formatter:
- Minified HTML — you received or copied HTML that was compressed to a single line. Formatting it makes it readable and editable.
- Exported HTML — tools like WordPress, Dreamweaver, or website builders often export poorly formatted HTML.
- Pasted HTML from a client — clients copy-paste from Word, email, or websites. The result is usually a formatting nightmare.
- Code review preparation — you want consistent formatting before doing a diff. See our free code diff viewer.
- Documentation or blog posts — cleaning up HTML before pasting it into a CMS or markdown file.
- Learning HTML structure — students and beginners use formatted HTML to understand nesting and hierarchy.
How to Format HTML Online in 3 Steps
- Open the code formatter and select HTML from the language dropdown.
- Paste your HTML into the input box — works with partial HTML snippets or full documents.
- Set your tab width (2 or 4 spaces) and print width, then click Format Code.
Formatted output appears immediately in the output box. Use the Copy button to grab it, or Download to save it as a file.
Tip: if you're formatting HTML that includes inline CSS or JavaScript, the formatter handles those blocks too — CSS gets formatted as CSS, script blocks as JavaScript.
HTML Formatting vs HTML Validation — What's the Difference?
Formatting and validation are different operations:
| Operation | What it does | Tool to use |
|---|---|---|
| Formatting | Fixes whitespace, indentation, line breaks | This formatter |
| Validation | Checks HTML5 spec compliance (missing tags, wrong nesting) | W3C Validator |
| Linting | Catches accessibility issues, deprecated tags | HTMLHint, axe |
If your HTML has a broken structure (unclosed tags, malformed attributes), the formatter will still try to format it — but the output may look odd. Fix validation errors first, then format.
Does It Support HTML Templates (Jinja, Handlebars, ERB)?
The formatter uses Prettier's HTML parser, which supports plain HTML and some component-based templates. It works well with:
- Plain HTML5 documents
- HTML with inline CSS and script blocks
- HTML fragments (partial HTML without doctype)
It may produce unexpected results with Jinja2, Handlebars, ERB, or other server-side template syntax, since those use curly braces and control flow tags that Prettier doesn't know about. For those cases, use your framework's specific formatter.
Format Your HTML Now — Free, No Signup
Paste messy HTML and get clean, properly indented output in seconds. Runs entirely in your browser.
Open Free Code FormatterFrequently Asked Questions
Can it format a full HTML document including doctype?
Yes. Paste the entire file including the DOCTYPE declaration — the formatter handles it correctly.
Will it change my HTML structure or remove elements?
No. The formatter only changes whitespace and line breaks. It never removes, adds, or reorders your HTML elements.
What if my HTML has inline JavaScript?
Script blocks are formatted as JavaScript. Style blocks are formatted as CSS. Both are handled in a single pass.
Does it work on mobile and tablets?
Yes. The formatter runs in any modern browser — Safari on iPhone, Chrome on Android, or any tablet. No app required.