Heading Structure Checker – Free Online Tool | Awesome Toolkit

Heading Structure Checker

Paste HTML and visualize the H1–H6 heading hierarchy. Flags missing H1, duplicate H1, and skipped levels.

By Marshkalk

Heading Structure Checker

Paste the HTML source of a page to visualize the heading hierarchy (H1-H6) as an indented tree. The checker flags common SEO and accessibility issues.

Issues detected

  • Missing H1: every page should have exactly one H1 tag
  • Multiple H1s: only one H1 per page is recommended
  • Skipped levels: e.g. H2 followed by H4 without an H3 in between
  • Empty headings: heading tags with no text content

Why heading structure matters

A well-structured heading hierarchy serves two purposes:

  • SEO: search engines use headings to understand page structure and key topics. A single descriptive H1 that includes the primary keyword helps Google understand what the page is about.
  • Accessibility (WCAG): screen readers navigate pages using headings. A logical hierarchy (H1 → H2 → H3) lets visually impaired users jump between sections efficiently. Skipping levels breaks this navigation.

Best practices

  • Use exactly one H1 per page, it should describe the page's primary topic
  • Use H2 for major sections, H3 for subsections within H2, and so on
  • Never skip levels (e.g. from H2 to H4) just for visual styling, use CSS instead
  • Keep headings descriptive and concise, they appear in screen reader navigation lists

UK and EU accessibility requirements

Heading structure is not just an SEO preference in the UK and EU, it is a legal requirement for many organisations:

  • Public Sector Bodies Accessibility Regulations 2018 (PSBAR): all UK public sector websites must meet WCAG 2.1 Level AA. A missing or skipped heading hierarchy violates success criterion 1.3.1 (Info and Relationships). Non-compliance can result in enforcement action by the Cabinet Office.
  • Equality Act 2010: private sector websites used by the public must be reasonably accessible to disabled users. While heading structure alone is rarely the basis of a claim, it is part of the evidence chain in accessibility audits.
  • European Accessibility Act (EAA), June 2025: applies to private sector businesses in the EU providing digital products and services. Websites of e-commerce, banking, e-books, and transport services must meet WCAG 2.1 AA from 28 June 2025. UK businesses serving EU customers are affected. Proper heading structure is directly required by WCAG 1.3.1.

Free tools to audit heading structure on live pages: WAVE (webaim.org/resources/wave), axe DevTools (browser extension), and the Accessibility tab in Chrome DevTools (which shows the Accessibility Tree).