What is HTML heading hierarchy?

HTML heading hierarchy refers to the structured arrangement of heading elements (H1 through H6) in a web document. These headings create a logical outline of content, similar to chapters and sections in a book. Proper heading hierarchy is essential for accessibility, SEO, and content organization. Screen readers use headings to help visually impaired users navigate pages, while search engines rely on them to understand content structure and relevance.

A well-structured heading hierarchy follows a descending order—starting with H1 as the main title, followed by H2 for major sections, H3 for subsections, and so on. Skipping heading levels (e.g., jumping from H1 to H4) can confuse both users and search engines, potentially harming accessibility compliance and search rankings.

Tool description

The HTML Heading Hierarchy Visualizer extracts and displays all heading elements from HTML code in an interactive tree structure. It parses your HTML input and organizes headings into a visual hierarchy that reflects their actual document outline. The tool also provides statistical breakdowns showing the count of each heading level used in your content.

Examples

Input HTML:

<h1>Website Title</h1>
<h2>Introduction</h2>
<p>Some content here...</p>
<h2>Main Features</h2>
<h3>Feature One</h3>
<h3>Feature Two</h3>
<h4>Sub-feature</h4>
<h2>Conclusion</h2>

Output Tree:

H1: Website Title
├── H2: Introduction
├── H2: Main Features
│   ├── H3: Feature One
│   └── H3: Feature Two
│       └── H4: Sub-feature
└── H2: Conclusion

Statistics:

  • Total Headings: 7
  • H1: 1, H2: 3, H3: 2, H4: 1, H5: 0, H6: 0

Features

  • Interactive tree visualization: View heading hierarchy as an expandable/collapsible tree structure
  • Real-time parsing: Instantly analyze HTML as you type or paste content
  • Heading statistics: Get counts for each heading level (H1-H6) and total headings
  • Configurable expansion depth: Control how many levels are expanded by default
  • Expand/collapse all: Toggle between fully expanded and collapsed tree views

Use cases

  • SEO auditing: Verify that page headings follow a logical structure for better search engine indexing and ranking
  • Accessibility testing: Ensure heading hierarchy meets WCAG guidelines for screen reader navigation
  • Content review: Quickly visualize document outline before publishing articles or documentation
  • Website migration: Analyze existing page structures when redesigning or migrating content to a new platform
  • Code review: Check heading structure in HTML templates during development and quality assurance