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Heading Structure Analyzer

Paste HTML and get a clean H1–H6 outline plus a list of real problems: missing or duplicated H1, skipped levels, and headings that are too long.

By Hongtao Ren · Updated 2026-09-22

SerpPrism's Heading Structure Analyzer is a free online tool that turns pasted HTML into a clean H1–H6 outline and flags real structural problems: missing or duplicated H1s, skipped levels, and headings too long to scan. There is no sign-up and nothing is uploaded — the analysis runs entirely in your browser. It is built for SEOs, content editors, and developers who want a thirty-second structure check before publishing. Paste a chunk of HTML and this builds the document outline, then flags the problems that actually matter. It does not score you out of 100 — it tells you which specific headings are wrong and why.

How to use it

1. Copy the rendered HTML of your page (view-source, or the element tree in devtools).
2. Paste it in. The outline and the issue list build instantly.
3. Fix the flagged headings in order — missing H1 first, then skipped levels.

Skipped levels are a real problem, just a small one

Jumping from H1 straight to H3 breaks the outline that screen readers build for navigation. A user jumping between headings hears 'level 3' with no level 2 above it, which makes the document hierarchy ambiguous.

For search engines the effect is minor — Google has said heading order is not a strong ranking signal. The accessibility argument is the solid one, and it is the reason to fix it.

One H1, and it should match what the page is about

Multiple H1s are not an error in HTML5 and Google has explicitly said it handles them fine. But in practice a page with three H1s usually has three competing ideas about what it is, and that confusion shows up in the snippet it earns.

If your theme puts the site name in an H1 on every page, that is a template problem worth fixing — your page title deserves that slot.

How to read the outline once you have it

Scan the H2s alone first. If the H2 list does not read like a table of contents for the page, the page has no structure — it has paragraphs with bigger text above them. That is the finding worth acting on, and it is invisible if you only look at the issue count.

Then check whether any section is doing two jobs. A heading like 'Pricing and support' usually means two sections were merged for convenience, and splitting them makes both easier to find.

Finally, look at the depth. If you have H4s under H2s with no H3 between them, the outline is skipping a level. Either promote the H4 or introduce the missing H3 — but if a section needs four levels of nesting, it is usually a sign the page is trying to cover too much.

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