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Heading Structure Validator

Check a page for skipped heading levels, missing or multiple H1s and empty headings.

Heading structure must form a logical outline: exactly one H1, no skipped levels, and no empty headings. Screen reader users navigate by heading, so a page that jumps from H1 to H3 loses a rung on the ladder. This validator lists the outline and flags every break against WCAG 1.3.1 and 2.4.6.

Runs in your browser
Checks
Skipped levels, missing H1, multiple H1s, empty headings and the starting level
WCAG criteria
1.3.1 Info and Relationships, 2.4.6 Headings and Labels
Privacy
Runs entirely in your browser — nothing is uploaded
Cost
Free, unlimited, no sign-up

Frequently asked questions

Why does skipping a heading level matter?

Screen reader users jump between headings to navigate. Levels convey nesting, so a jump from H1 to H3 implies a missing section — the listener cannot tell whether they have skipped content or the author has skipped a number.

Can I have more than one H1?

HTML5 permits it inside sectioning elements, but assistive technology support is inconsistent and it makes the outline ambiguous. One H1 per page remains the safest choice.

How to use the heading structure validator

  1. 1Enter or paste your html.
  2. 2Turn "Require exactly one H1" on or off as needed.
  3. 3The result appears immediately — copy or download it.

Embed this tool

Put the working heading structure validator on your own site. It runs in your visitors' browsers exactly as it does here — free, no account, nothing uploaded.

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