Heading Structure Checker
Paste your page HTML to see its h1–h6 document outline and instantly flag skipped levels, multiple h1s, and empty headings. A clean heading hierarchy is part of WCAG 2.2 Success Criterion 1.3.1, and it is how many screen reader users navigate a page.
In your browser, right-click the page → “View Page Source” (or press Ctrl/Cmd + U), copy it, and paste it below. Everything is analyzed locally in your browser. Nothing is uploaded.
Building a Logical Heading Outline for WCAG 1.3.1
Headings are the backbone of a page’s structure. Sighted users scan them visually; screen reader users pull up a list of headings or jump between them to move around quickly. When the heading levels form a logical, gap-free outline, everyone can build the same mental model of the page. WCAG 2.2 Success Criterion 1.3.1 (Info and Relationships, Level A) requires that this visual structure is also expressed in the markup, which means using real <h1>–<h6> elements in the right order.
Start at h1
Begin each page with a single h1 that names its main content. Everything below it nests under that top-level heading.
Do not skip levels
Going down the outline, move one level at a time: an h2 is followed by an h3, not an h4. You can jump back up any number of levels when a new section starts.
Never leave a heading empty
An empty heading announces structure that is not there. If you only need the visual style, use styled text or CSS instead of a heading element.
Do not choose levels by size
Pick heading levels by their place in the outline, not by how big the text looks. Use CSS to control appearance so the underlying structure stays correct.
What this tool checks, and what it can’t
This checker parses the HTML you paste, reads every <h1>–<h6> and role="heading" element, and builds the outline in document order. It flags a missing or duplicated h1, skipped levels, and empty headings. What no automated tool can do is judge whether each heading accurately describesthe section it introduces. That is WCAG 2.4.6 and always needs a human. Automated scanning reliably covers about 30–40% of WCAG success criteria; the rest require manual review.
Frequently Asked Questions
What WCAG rule does heading structure relate to?
Heading structure is primarily covered by WCAG 2.2 Success Criterion 1.3.1 Info and Relationships (Level A), which requires that structure conveyed visually is also programmatically determinable. Headings also relate to SC 2.4.6 Headings and Labels (Level AA), which requires that headings describe their topic or purpose.
Why do skipped heading levels matter?
Screen reader users often navigate a page by jumping between headings. Heading levels form an outline, and skipping a level going down (for example an h2 followed directly by an h4) breaks that outline, making the page structure harder to understand and navigate.
Should a page have only one h1?
A single h1 that names the main content is the most reliable pattern and is widely recommended. The HTML5 outline algorithm technically allows multiple h1s inside sectioning elements, but browser and assistive-technology support for that algorithm is inconsistent, so one h1 per page remains the safest choice.
Does this tool upload my HTML anywhere?
No. The heading structure checker parses your HTML entirely in your browser using the built-in HTML parser. Nothing you paste is sent to a server. To scan a live URL and every page on your site automatically, use the CompliaScan site scanner.
Can automated tools fully verify heading structure?
Automated tools can reliably detect missing h1s, skipped levels, and empty headings. What they cannot judge is whether each heading accurately describes the content it introduces, which is a requirement of SC 2.4.6 and always needs human review. Automated scanning reliably covers roughly 30–40% of WCAG success criteria.
Check Heading Structure Across Your Whole Site
Checking one page at a time by hand? Our automated scanner crawls your pages and validates heading structure, plus contrast, alt text, form labels, keyboard traps, and 100+ more WCAG 2.2 checks. Free scan, no signup required.
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