free tool

Heading structure analyzer

AI engines lift a section, not a wall of text — clean heading hierarchy makes each passage extractable. Paste HTML/markdown or fetch a URL to see the H1–H6 outline and structural issues.

What this tool checks

A heading structure checker validates that a page's headings form one logical outline: a single H1 that names the page, then H2s and H3s that nest without skipping a level (never jumping H2 straight to H4). A broken outline hides your document's structure from search crawlers and AI answer engines, which walk the heading tree to learn what each section answers — so a clean hierarchy makes your content easier to index, feature in snippets, and quote in AI Overviews.

What it looks at

Single H1
The page has exactly one top-level heading that names the whole page; zero or multiple H1s blur the primary-topic signal crawlers rely on.
No skipped levels
You never jump from H2 to H4 — each step down moves exactly one level, keeping the outline parseable by machines and screen readers.
Logical nesting
Every H3 sits under an H2 and every H4 under an H3, forming a tree that mirrors the content's actual structure.
Empty headings
An empty heading tag (no text) creates a phantom node in the outline and should be removed or given text.
Top-to-bottom order
Headings appear in document order that matches the visible reading order. Returning to a higher level to start a new section (H3 back to H2) is fine — only skipping levels on the way down (H2 to H4) breaks the outline.
HTML and markdown parity
The same rules apply whether you paste rendered HTML (`<h2>`) or markdown (`##`), because both resolve to the same heading tree.

How to use it

  1. Paste your HTML or markdown into the checker, or enter a URL to fetch the live page.
  2. Review the flagged issues — a missing or duplicate H1, and any skipped level such as H2 jumping to H4.
  3. Fix the outline so there is one H1 and each heading steps down a single level at a time, then re-check.

Frequently asked questions

Why should a page have only one H1?

The H1 tells crawlers and AI engines the page's main topic in one line, so a single H1 keeps that signal unambiguous. Multiple H1s split the primary-topic signal and can flatten your outline, while zero H1 leaves the page with no titled root.

Does skipping from H2 to H4 hurt SEO?

Yes — a skipped level breaks the logical outline that crawlers, screen readers, and AI answer engines use to map sections to subtopics. It rarely triggers a penalty on its own, but it weakens content parsing and accessibility, which both feed ranking and citation.

What is the correct heading order?

Start with one H1, then use H2 for main sections and H3 for subpoints within them, never skipping a level on the way down. You can jump back up (H3 to H2 for a new section), but each step deeper should move only one level at a time.

Can I check markdown as well as HTML?

Yes — paste markdown (`#`, `##`, `###`) or HTML (`<h1>`–`<h6>`), or fetch a live URL, and the checker maps all three to the same heading tree. The hierarchy rules are identical regardless of the source format.

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