Free Heading Gap Detector

Check any web page for skipped heading levels and malformed heading hierarchy. See a visual heading tree, get a hierarchy score, and learn exactly which heading tags need to be fixed for better SEO and accessibility.

Why Heading Hierarchy Matters

HTML heading tags (H1 through H6) create the document outline of every web page. Search engines use this outline to understand the structure and topical hierarchy of your content. When heading levels are skipped — for example, jumping from H1 to H3 without an H2 — the outline becomes broken. This makes it harder for crawlers to determine which sections are main topics versus supporting details.

Beyond SEO, heading hierarchy is critical for accessibility. Screen readers rely on heading levels to let visually impaired users navigate the page. Skipped levels create a confusing navigation experience and can make your site non-compliant with WCAG 2.1 guidelines.

Common Heading Hierarchy Mistakes

How to Use This Tool

1. Enter a URL — Paste any web page URL into the input field. The tool fetches the live page and extracts all heading tags (H1 through H6).
2. Click "Check" — The tool analyzes the heading hierarchy for skipped levels, missing H1, multiple H1 tags, and empty headings.
3. Review the score — See your heading hierarchy score from 0 to 100. Scores above 80 indicate a clean structure. Below 50 means significant gaps need fixing.
4. Read the recommendations — Each issue comes with a specific fix recommendation telling you exactly what to change.
5. Study the heading tree — The visual tree shows your full heading outline with indentation matching the nesting depth. Gaps are highlighted in red so you can see exactly where levels are skipped.
6. Check level distribution — The bar chart shows how many of each heading level you have, making it easy to spot over-reliance on a single level or unused levels.

Frequently Asked Questions

What is a heading gap in HTML?

A heading gap occurs when heading levels are skipped in the document hierarchy. For example, jumping from H1 directly to H3 without an H2 in between creates a gap. This breaks the logical outline of the page and can confuse both screen readers and search engine crawlers.

Do skipped heading levels hurt SEO?

Skipped heading levels signal a disorganized content structure to search engines. While Google does not issue a direct penalty for heading gaps, a clean heading hierarchy helps crawlers understand your content better, which can improve indexing and rankings. Proper heading structure also improves accessibility and user experience, both of which are ranking factors.

What is the correct heading hierarchy?

The correct heading hierarchy follows a sequential nesting order: H1 for the main page title, H2 for major sections, H3 for subsections within an H2, H4 for sub-subsections, and so on. You should never skip a level going deeper — for example, do not jump from H2 to H4. Going back up to a higher level (e.g., H3 back to H2) is perfectly fine and expected.

How many H1 tags should a page have?

Best practice is to use exactly one H1 tag per page. The H1 serves as the primary heading and should clearly describe the page's main topic. Multiple H1 tags dilute the topical signal and create a flat heading structure that is harder for search engines and assistive technologies to parse.

How do I fix heading hierarchy issues?

Start by mapping out your content outline. Use the Heading Gap Detector to identify exactly where levels are skipped. Then adjust the heading tags so they follow a sequential order: H1 then H2 then H3 and so on. If your CMS or theme is generating incorrect heading levels, update the template. For component-based sites (React, Vue), check that reusable components use appropriate heading levels relative to where they are placed on the page.