Digital Hub Lab
Heading Structure Checker
Turn HTML or a heading list into a clear outline and find structural issues worth reviewing.
Turn the headings from a page into a readable outline and identify patterns worth reviewing. The checker focuses on useful structural guidance rather than treating every unusual level as an automatic failure.
Page outline review
Check a heading structure
Paste HTML containing headings, or a Markdown-style list beginning with # symbols.
Page outline
Review notes
Private by design: this tool runs in your browser. What you enter is not sent to or stored by Digital Hub Zone.
How to check your headings
- Copy the relevant HTML from your editor or enter each heading as a line beginning with one to six # symbols.
- Select Check headings to create the page outline.
- Review missing main headings, empty headings and jumps between levels.
- Compare the outline with the meaning of the page—not just its visual appearance.
What a clear outline looks like
The main page heading should describe the overall subject. H2 headings normally introduce the main sections, while H3 and lower levels group ideas inside those sections. Heading levels should communicate relationships rather than being chosen simply because of their font size.
Use the notes as review prompts
More than one H1 can be valid in modern HTML, and a skipped level is not automatically a WCAG failure. The important question is whether readers—especially people navigating with assistive technology—can understand the page structure and move through it efficiently.