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Heading Structure Checker

A heading structure checker shows the outline of a page built from its H1 to H6 headings. Paste your HTML and this free tool lists every heading in order as a nested outline, counts each level and points out empty headings, skipped levels and repeated heading text, so you can see the structure readers and search engines see.

By ToxicBacklink – Free SEO Tools & Backlink Checker · Last updated 16 October 2026 100% In-Browser · Zero Data Retention
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This tool checks the HTML you paste. It does not visit your page, run your scripts or see your CSS.

What is a heading structure checker and when should you use it?

Headings break a page into sections and give each one a name. Their order forms an outline, much like a table of contents. Google uses headings as one of the sources for the title link in search results. Check the rest of your markup with the Image Alt Text Checker and the Internal Link Counter, test your copy with the Readability Score Checker, or verify your head title with the Title Tag Length Checker.

How do you use it?

  1. Paste the HTML of your page, or upload the file.
  2. Press Check.
  3. Read the outline from top to bottom.
  4. Review the notes and fix what was not intended.

Working on a comprehensive technical audit? Browse all free SEO tools to discover the next step in your workflow, or contact our technical support team if you require a specialized custom utility.

Result interpretation & practical applications

When evaluating the output of the heading structure checker, review the parsed metrics against your specific site architecture. Outputs are formatted for direct implementation into your HTML source, web server configuration, or Google Search Console audit files.

Always inspect generated values for contextual nuance. Automated tools highlight structural patterns, but manual verification confirms that technical directives align with your overarching SEO strategy.

Technical rules and limitations

  • Google creates title links from several sources, including the main visible title and heading elements.
  • Google says it can be confusing if several headings carry the same visual weight and prominence.
  • This tool can't see your CSS, so it can't judge which heading looks most prominent.

These rules come from Google's guide to title links in search results and the W3C Headings and Sections specification.

Common mistakes and troubleshooting

  • Using a heading tag only to make text bigger.
  • Leaving an empty heading in a template.
  • Giving several sections the same heading text.

No tool can promise how a search engine will crawl, index, or rank your pages. This tool generates and validates code against documented technical specifications; you determine where to deploy it, and you should always test changes on staging environments first. Google publishes extensive guidelines in Search Central on evaluating third-party SEO tools and advice. Learn more about our technical testing standards on our about us page, or explore full site audits on our pricing page.

Related free tools & workflows

Browse all Advanced On-Page SEO Tools →

Authoritative Technical Documentation & Standards

This tool executes logic aligned with official technical documentation and search engine webmaster standards:

Heading Structure Checker questions

Is more than one H1 a problem? ↓

This tool only reports the number; it doesn't call it an error.

What is a skipped level? ↓

A jump such as h2 straight to h4. The tool flags it so you can check it was intended.

Does it read my CSS? ↓

No. It only reads the HTML elements.

Is this tool free? ↓

Yes. It is completely free to use and requires no registration or subscription.

Does this tool visit my website or store my files? ↓

No. It executes entirely in your local browser runtime. Your inputs and results are never stored or logged on our servers.

Ready for the next step in your audit?

ToxicBacklink – Free SEO Tools & Backlink Checker builds fast, browser-based utilities for webmasters, developers, and SEO professionals. Each tool executes locally, shows exact modifications, and follows published specifications. Read more about us, check our how it works guide, browse all tools, or return to the home page.