HTML Formatter

How HTML Formatter works

Indent nested HTML so the structure is readable, without changing any markup. Everything happens inside this page: the tool reads your input, runs the calculation or conversion locally, and hands the result back to you. Nothing is transmitted, because there is no backend to transmit it to.

That design choice is deliberate. Most free tool sites upload your files to a server, process them there, and quietly keep a copy. Toolcin cannot do that — the site is a set of static files. If your connection dropped the moment the page finished loading, every tool would still work.

What it does to the markup

The input is tokenised into tags and text, then reprinted with one element per line and a consistent indent. Void elements — br, img, input, meta, link, hr and the rest — are recognised so they do not get an invented closing tag.

Text inside an element stays on its own line rather than being merged or reflowed. That keeps the meaning identical; the only thing that changes is whitespace between tags.

Where formatting can change rendering

Whitespace between inline elements is significant in HTML. A formatter that puts every span on a new line can introduce a visible gap between words, because the newline becomes a space. Inline elements are the one place where pretty-printing is not purely cosmetic.

If the formatted output renders differently, the usual cause is a text node that was moved across a tag boundary. Keep the original file when the layout is fragile — for example, an inline-block navigation built without flexbox.

Formatting is not validating

An unclosed tag or a duplicated attribute can still be reprinted in a readable shape, because the tokeniser is tolerant. Use a real validator when correctness matters; use this when you need to read someone else's minified markup or diff two versions of a template.

The output is meant to be pasted into an editor, not served. Minification for delivery is a separate step, and the CSS minifier covers that direction.

Good to know

• Works offline once loaded, including on flights and in locked-down networks.
• No file size limit beyond your device's own memory.
• Free to use, with no account and no usage counter.
• Results are produced locally, so they are not logged or shared with anyone.

Questions