Quick Tools

HTML Formatter

Paste or upload HTML and format it with custom tab size. Copy or download the result in your browser. No signup.

Formatting happens in your browser. No signup, no upload, no server.

HTML Formatter — Beautify and Indent HTML Code Online

Properly indented HTML is easier to read, easier to debug, and easier to maintain. When you receive minified markup from an API, copy a snippet from a third-party tool, or write HTML by hand without your editor's auto-format, the result is often a wall of text with no visual structure. An HTML formatter restores that structure in one step, using your preferred indentation width and nothing more.

This tool runs entirely in your browser. Your HTML never leaves your device. Paste it in, choose an indent size, and format. Upload an .html file, download the result, or copy the formatted output to your clipboard. No signup, no server, no logging.

Why beautify HTML

Human-readable markup matters even if browsers do not care about whitespace. When every tag starts on a new line and nests cleanly, you can:

  • Spot structural mistakes faster. A missing closing tag or an unclosed element is obvious when the indentation does not match.
  • Review minified output. Third-party widgets, email templates, and inline scripts often arrive minified. Formatting them makes them reviewable.
  • Share snippets with teammates. Copy-pasted HTML in documentation, issue trackers, or chat is far easier to read when it is indented.
  • Edit before reformatting. Because formatting happens in place, you can tweak the markup and format again in the same textarea.

An HTML formatter is not a validator. It will not tell you whether your document is well-formed or semantically correct. It will, however, make the structure visible so you can spot problems yourself.

How to use

Paste or type HTML

Open the HTML source textarea and paste your markup directly. The editor supports multi-line input, so a full page of HTML works the same way as a short snippet. As you type, line numbers on the left update automatically so you can reference specific lines.

Set the indent size

The Indent size field controls how many spaces each nesting level uses. The default is 2, which matches the convention used by many style guides. You can raise it to 4 or 8 if you prefer deeper indentation, or lower it to 1 for compact output. The field accepts values from 1 to 8.

Format HTML

Click Format HTML to beautify the content of the textarea. The formatter indents nested elements, adds line breaks between tags, and aligns attributes over multiple lines when they make the result more readable. If the textarea is empty, you will see a friendly prompt asking you to paste or upload HTML first.

Upload a file

Use Upload file to open an .html or .htm file from your computer. The file is read with the browser's FileReader API and placed into the editor. No file is uploaded to any server. Files larger than 1 MB are rejected with a message asking you to use a smaller file.

Download the result

After formatting, click Download HTML to save the current content as formatted.html. The file is generated from a Blob and downloaded through a temporary object URL, the same way a browser would handle a "Save As" action.

Copy the formatted output

Click Copy HTML to write the editor content to your clipboard. A short confirmation appears so you know the copy succeeded. If the clipboard API is unavailable, the button fails silently and the content stays in the editor for manual selection.

Clear the editor

Click Clear editor to empty the textarea. This is useful when you want to start over with a fresh snippet without reloading the page.

Example

Here is a typical before-and-after. The input is a minified, single-line fragment taken from a real page. After formatting with an indent size of 2, the same fragment becomes readable.

Before — minified:

<!DOCTYPE html><html><head><meta charset="UTF-8"><title>Demo</title></head><body><article><h1>Hello, world</h1><p>This is a <strong>demo</strong> page.</p></article></body></html>

After — formatted (indent size 2):

<!DOCTYPE html>
<html>
  <head>
    <meta charset="UTF-8" />
    <title>Demo</title>
  </head>
  <body>
    <article>
      <h1>Hello, world</h1>
      <p>This is a <strong>demo</strong> page.</p>
    </article>
  </body>
</html>

Notice how the nesting is now visible. The <head> block sits inside <html>, the <article> wraps the heading and paragraph, and the inline <strong> element is easy to locate inside the sentence. If the original HTML had a structural problem, such as an unclosed <p> tag, that problem is easier to spot once the indentation is consistent.

Tips for cleaner output

  • Paste the whole document when possible. Formatting a fragment works, but the best results come from complete HTML that includes the <html>, <head>, and <body> structure.
  • Review self-closing syntax. The formatter will preserve the tags you write. If your source uses <br> instead of <br />, that choice remains after formatting.
  • Use a larger indent for deeply nested markup. Email templates and legacy pages can nest many levels deep. An indent size of 4 or 8 makes those trees easier to follow.
  • Format, edit, format again. Because the formatted output replaces the textarea content, you can make a small change and re-run the formatter to keep the result tidy.

FAQ

Does the formatter upload my HTML to a server?

No. The entire process runs in your browser using client-side JavaScript. Files are read with FileReader and output is generated from a local Blob. Nothing leaves your device.

What if my HTML is invalid or not well-formed?

The formatter will still attempt to produce indented output from whatever you paste. It does not validate your markup. If the input is malformed, the result may not be ideal, but the tool will not crash. If something goes wrong during formatting, a friendly message appears instead of an empty screen.

Can I format HTML fragments, or only full documents?

Both. Paste a snippet like a single <div> block or an entire page. The formatter indents based on nesting, so it works with any well-structured markup.

How large can the input be?

There is no hard limit for paste input, but the editor is designed for everyday markup. File uploads are capped at 1 MB. If you need to format something larger, consider splitting it into smaller pieces.

Does the formatter change my code in other ways?

No. It only adjusts whitespace: indentation, line breaks, and wrapping of long lines. It does not rename attributes, reorder elements, or strip your comments.

Can I use tabs instead of spaces?

The indent size field controls the number of spaces per level. If you prefer tabs, you can set the indent size to 1 and convert spaces to tabs in your own editor after copying the result. The formatter itself uses spaces.

Related tools

  • CSS Formatter — beautify and indent CSS stylesheets with the same browser-side approach.