Heading Order Checker
Check that heading levels descend one step at a time and form a real outline.
About this tool
Walks a page's headings in document order and reports every place the level jumps more than one step, plus the outline the page actually presents.
This matters for a specific reason. A screen reader user navigating a long page moves between headings, and the level is the only signal telling them whether the next heading opens a subsection or a new topic. When an h2 is followed by an h4 because the smaller size looked better, that user hears a sub-subsection of a section that was never announced.
Sighted readers get the same information from size and spacing, which is why this breaks so quietly: the page looks fine and the structure underneath it is wrong.
A skipped level is not a ranking problem. It is a usability one, and it is usually a two-character fix.
Common questions
Is skipping a heading level bad for SEO?
Not directly. Search engines cope with imperfect heading structures easily. The cost is to people using a screen reader, for whom the level is the only structural cue there is.
Can a page have more than one h1?
HTML allows it and screen readers handle it. It is still usually a sign that a template is emitting the site name and the page title at the same level, which makes the outline less useful than it could be.
What if I want a small heading?
Use the right level and style it. The level is structure and the size is presentation; a class or a bit of CSS keeps the two separate, which is exactly what they should be.
Why does the first heading matter?
A page that starts at h2 or h3 has no top level, so everything on it is a subsection of nothing. It is the same problem as a skipped level, at the point where it is most visible.