Heading Structure (H1–H6) Checker
Paste a page's HTML or Markdown and see its heading outline as a tree, with the problems flagged: missing or multiple H1s, skipped levels, empty headings, and headings that aren't phrased as anything a reader would search.
- Instant·Runs in your browser
- No signup
- Free
Page source or Markdown
Paste HTML or Markdown
You'll see the heading outline as a tree, with duplicate H1s, skipped levels and empty headings flagged.
Next step
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How to use it
- 1Paste the page source (HTML) or the Markdown draft.
- 2Read the outline tree — indentation shows nesting.
- 3Fix any issues listed: one H1, no skipped levels, no empties.
- 4Turn key H2s into questions to match how people ask.
Frequently asked
How many H1 tags should a page have?
One. HTML5 technically allows more, but Google’s guidance and every AI extraction pipeline treat the H1 as the page’s title. Two H1s means a coin toss.
Do skipped heading levels hurt SEO?
Not directly as a ranking factor, but a jump from H2 to H4 breaks the outline that screen readers and content extractors build, and AI engines use that outline to decide which passage answers what.
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