Headings Are an Outline

What this is. HTML gives you six heading levels, h1 through h6. They exist to describe the structure of your content, exactly like the outline of an essay.

h1 is the topic of the page. h2 marks its major sections. h3 marks subsections within those. And so on.

✦ Why this matters more than it looks like it should

Screen reader users navigate by jumping between headings, the same way a sighted reader scans a page. If your headings are an accurate outline, they can move through your site quickly. If you picked h4 because you wanted smaller text, their outline is nonsense and they have to read everything in order. Size is a CSS decision. Level is a meaning decision.

The rules that matter. One h1 per page, naming what the page is about. Never skip a level going down, so no h2 followed directly by an h4. And never choose a level for its size, because that is what CSS is for.