HTML Heading Structure Checker
Paste your HTML and get the page outline as a tree, with a list of problems such as a missing H1, skipped levels, empty headings and repeats.
Only the HTML you paste is read. Headings added later by scripts will not appear unless you copy the rendered HTML.
Worked examples
A skipped level
<h1>Shoes</h1> <h2>Running</h2> <h4>Trail runners</h4>
Warning: H4 "Trail runners" follows an H2 and skips H3.
Change the H4 to an H3, or add the missing H3 above it.
A tidy outline
<h1>A</h1> <h2>B</h2> <h3>C</h3> <h2>D</h2>
Good: The outline has one H1 and no skipped levels.
Going back up from H3 to H2 is always fine.
About HTML Heading Structure Checker
Headings are the skeleton of a web page. People skim them to decide whether a page answers their question, screen readers let blind visitors jump from one heading to the next, and search engines use them to understand which part of the page covers which topic. When the skeleton is broken, with two competing main headings, a section that jumps from H2 to H4 or a heading with nothing in it, the page is harder to use for everyone.
This checker reads the HTML you paste and lays the headings out as an outline, indented by level, with the number of words under each one. Below the outline it lists the faults it found: no H1, more than one H1, a first heading that is not the H1, skipped levels, empty headings, very long headings and headings that repeat word for word. Everything is worked out from the text you paste, so you can check a draft before it goes live.
How to use HTML Heading Structure Checker
- Open your page, view the page source, select everything and copy it.
- Paste the HTML into the box. The outline appears as soon as you paste.
- Read the checks list first. Problems come before warnings and notes.
- Use the outline and the word counts to see which sections are long, thin or out of order, then fix them in your editor and paste again.
Common uses
- Checking a new article before publishing it
- Auditing an old page that has been edited many times
- Making a page easier to navigate with a screen reader
- Checking that a template produces one H1 per page
Frequently asked questions
Should a page have only one H1?
HTML allows more than one, but a single H1 that names the main subject of the page is the clearest choice for readers and search engines. The checker raises a warning, not a problem, when it finds more than one.
Why does skipping a heading level matter?
Screen reader users move through a page by heading level, so a jump from H2 straight to H4 suggests that content is missing. Use the next level down for a sub-section, and change the look with styles instead of picking a smaller heading.
Does the order of headings affect rankings?
There is no known ranking rule about heading order, but a clear outline helps people understand and finish reading a page, and clear structure helps search engines work out what each section is about. It is good practice rather than a trick.
Why are my headings missing from the result?
Headings added by scripts after the page loads are not in the HTML that you see with View page source. Copy the rendered HTML from your browser's inspector instead, or check the page from the template.
How long should a heading be?
Short enough to read at a glance. The checker notes headings over 70 characters, because longer ones often read like sentences and are harder to scan.