Free Heading Structure Checker — Analyze H1-H6 Hierarchy

How It Works

Paste your HTML code or fetch a URL to extract all heading tags (H1-H6). The tool maps the heading hierarchy as a color-coded visual tree, identifies structural issues like missing H1s, multiple H1s, or skipped heading levels, and provides a distribution chart showing the count of each heading level. It gives you a complete picture of your page's semantic structure.

Why It Matters for SEO

Heading tags create the semantic structure of your page, helping both search engines and screen readers understand your content hierarchy. Google uses headings to understand the topical organization of your content — a proper H1→H2→H3 structure signals clear content organization. According to Google's John Mueller, headings help Google understand the content on a page. Skipped levels (e.g., H1→H3) violate WCAG accessibility guidelines, which can affect your site's compliance and user experience for people using assistive technologies.

When to Use This Tool

Before publishing a new blog post or page to verify proper heading structure
During an SEO audit to find heading issues across your site
When optimizing content that was written without SEO in mind
After a website migration to ensure heading structure was preserved
When checking accessibility compliance (WCAG 2.1 requires proper heading hierarchy)
When restructuring long-form content to improve readability and scannability

Key Concepts

Heading Tags (H1-H6)

HTML elements that define headings and subheadings in your content. H1 is the most important (main topic), followed by H2 (sections), H3 (subsections), and so on down to H6. They create a document outline that search engines and screen readers use to navigate content.

Semantic HTML

HTML code that uses elements according to their intended meaning, not just for visual appearance. Heading tags are a key part of semantic HTML — using H1 for the main title and H2-H6 for subheadings creates a meaningful document structure that helps both machines and humans understand your content.

Document Outline

The hierarchical structure of headings on a page. A well-formed document outline starts with a single H1, followed by H2 sections, each containing H3 subsections, and so on. Google uses this outline to understand content organization and topical focus.

WCAG (Web Content Accessibility Guidelines)

International standards for web accessibility. WCAG 2.1 requires proper heading hierarchy (no skipped levels) so that screen readers can navigate content effectively. Heading structure is assessed under WCAG 1.3.1 (Info and Relationships) and 2.4.6 (Headings and Labels).

Best Practices

Use exactly one H1 per page — it should be your main topic/headline
Organize content with H2 for main sections, H3 for subsections, H4 for sub-subsections
Never skip heading levels (e.g., don't jump from H2 to H4) — this breaks the document outline
Include target keywords in H1 and H2 tags naturally — they carry more weight than body text
Make headings descriptive — they should summarize the section content for both users and crawlers
Keep headings concise: H1 under 70 chars, H2 under 60 chars, H3 under 50 chars
Use headings to break up long content — they improve readability and scannability
Don't use headings for visual styling — use CSS for font size and weight instead

Heading Structure Checker

How It Works

Why It Matters for SEO

When to Use This Tool

Key Concepts

Best Practices

Related SEO Tools

Frequently Asked Questions

How many H1 tags should a page have?

Do heading tags affect SEO rankings?

Can I skip heading levels?

What is the difference between H1 and title tag?

How should I structure headings for a long blog post?