Paste the HTML source of any page to see its headings as an indented H1-H6 outline. The checker flags a missing or repeated H1, skipped heading levels, empty and overly long headings, so you can fix SEO and accessibility problems quickly.
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How to use the Heading Structure Checker
Open the page in your browser and view its source (Ctrl+U or Cmd+Option+U).
Copy all the HTML and paste it into the box, or open a saved .html file.
Click Check headings; results also update as you type.
Read the problems list and the flagged lines in the outline.
Fix the headings in your template, then paste again to confirm.
Heading rules the checker tests
Check
Severity
Why it matters
No H1 on the page
Error
The main topic has no heading for users, assistive technology or search engines.
Empty heading
Error
Announced as a blank heading by screen readers; often a leftover from a template.
More than one H1
Warning
Valid HTML, but blurs which heading is the page title.
Skipped level (e.g. H2 → H4)
Warning
Implies a missing section and breaks the logical outline.
First heading is not the H1
Warning
Headings in the site header or menu come before the page title.
Heading over 120 characters
Warning
Long headings are hard to scan; move detail into a paragraph.
Duplicate heading text, hidden headings
Note
Worth a look: repeated labels and hidden headings are easy to miss.
Example of a clean outline
Level
Heading
H1
A Beginner's Guide to Indoor Plants
H2
Choosing the right plant
H3
Low-light plants
H3
Plants for sunny windows
H2
Watering basics
H3
How often to water
Tips for fixing heading problems
Turn decorative headings in sidebars and footers (like "Follow us") into styled paragraphs or give them the right level under a section.
If a theme wraps the site logo in an H1 on every page, change it to a div and keep the H1 for the page title.
Use the outline as a table of contents test: if it reads like a sensible summary of the page, the structure is good.
Frequently asked questions
What is a good heading structure?
A page should have one H1 describing its main topic, H2s for the main sections, H3s for sub-sections inside an H2, and so on. Levels should go down one at a time, so an H4 always sits under an H3. Going back up any number of levels, such as from H4 to H2, is fine.
Is it bad to have more than one H1?
The HTML standard allows several H1s and Google has said multiple H1s are not a problem for ranking. Still, one clear H1 makes the page topic obvious to users, screen readers and search engines, so it is the common best practice. The checker reports extra H1s as a warning, not an error.
Why are skipped heading levels a problem?
Screen reader users often jump between headings or list them to understand a page. A jump from H2 to H4 suggests a missing section and makes the structure confusing. WCAG technique G141 recommends nesting headings in order to convey the page structure.
Should headings be chosen for their size?
No. Pick the heading level for its place in the document structure and use CSS to set the size. A small-looking subtitle can still be an H2, and a large promotional line that isn't a section title should be a paragraph.
Why does the checker count headings in my navigation and footer?
They are part of the page outline, so screen readers announce them too. If you only want to review the article itself, tick the option to check only inside the main element.
Can I check a live URL?
Browsers can't read other websites' HTML directly for security reasons, so paste the page source instead. Use View Source in your browser to copy the original HTML. If headings are added by JavaScript, copy the rendered HTML from the developer tools Elements panel instead.
Is my HTML sent anywhere?
No. The HTML is parsed in your browser with the built-in DOM parser, scripts in it never run and nothing is uploaded.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.