H1, H2, H3. Heading tags as structure, not decoration.

What header tags actually are

HTML defines six heading tags: H1 through H6. They look like this:

<h1>Main topic of the page</h1>
<h2>A major section</h2>
<h3>A sub-point inside that section</h3>

That is the whole tag. What they do is define the document's outline. If you stripped every paragraph from a well-built page and left only the heading tree, you would still know what the page was about and what it covered. That is the test of a good heading structure: read only the headings and the page makes sense.

What heading tags are not: a styling tool. WordPress themes often encourage editors to pick a heading tag based on how large they want the text to look. That is the wrong instinct. Headings are structural. If you want a 40-pixel font, that is a CSS job, not an H1 job. Confusing the two is the single most common heading mistake we see in Perth small-business sites.

The accessibility case nobody mentions in SEO blogs

Screen readers (the assistive software a blind user runs to consume your page) navigate by heading. A user can press a single key to jump to the next H2, then a single key to jump to the next H3 inside it. If your headings are out of order or used for styling, the page becomes near-impossible to navigate without sight. That is not just an SEO problem. It is an accessibility problem. And under the Disability Discrimination Act 1992, Australian businesses have a legal interest in getting it right.

The good news is that fixing headings for screen readers also fixes them for SEO. The two requirements line up exactly. One job, two wins.

How Google and screen readers read the hierarchy

Both Google and screen readers treat your page as an outline tree. Imagine the table of contents in a non-fiction book:

H1: Australian Birds of the South-West
  H2: Chapter 1. Coastal birds
    H3: Pelicans
    H3: Cormorants
    H3: Terns
  H2: Chapter 2. Bushland birds
    H3: Honeyeaters
    H3: Wattlebirds

Google reads exactly that structure and uses it to understand which sub-topics your page covers. A user searching for "honeyeaters" who lands on this page can see (and Google can see) that your H3 about honeyeaters sits inside a chapter about bushland birds, which sits inside a book about south-west Australian birds. The topical context is preserved.

When the hierarchy is broken (an H3 with no H2 parent, two H1s, headings used for emphasis), the tree collapses. Google still indexes the page but loses confidence about what is what. Snippets become harder to extract. Topical authority signals get diluted. None of these are catastrophic on their own, but they compound across hundreds of pages.

The heading tree: how to build it

Five rules. They are surprisingly easy to follow once you know them.

1. One H1. The H1 names the topic of the entire page. There is one of them, at the top, and it contains your primary keyword.
2. H2 for major sections. Each major section of the page gets an H2. A typical 1,500-word cluster has between four and eight H2s. A 5,000-word pillar might have eight to twelve.
3. H3 inside H2 for sub-points. When an H2 section is long enough to need sub-divisions, use H3. Each H3 should belong to exactly one H2.
4. H4-H6 only when genuinely needed. On most pages you will never use H4. If you do, it is because a complex sub-section has its own sub-sections, which is rare in marketing content.
5. Never skip levels. Do not jump from H1 to H3, or from H2 to H4. Each level must be preceded by its parent.

That is the entire system. Build the tree first, write the body copy second.

Worked example: a service page tree

H1: Emergency electrician Perth
  H2: When to call an emergency electrician
    H3: Signs your wiring is dangerous
    H3: Signs you can wait until morning
  H2: What our callout covers
    H3: Residential callouts
    H3: Commercial callouts
  H2: Pricing and response time
  H2: Our service area
    H3: Perth metro
    H3: Joondalup, Cockburn and the southern suburbs
  H2: FAQ

This page reads cleanly even with just the headings. Every H3 has an H2 parent. The H1 contains the primary keyword. The structure tells Google the page is comprehensive on emergency electrical callouts in Perth, which is exactly what a searcher looking for that service wants to see.

H1, H2, H3: specific rules for each

H1 rules

• One per page. No exceptions in practice.
• 40 to 70 characters of normal-width text.
• Contains the primary keyword the page targets.
• Reads as a natural sentence or fragment, not a list of keywords.
• Different in wording from the title tag, even if they share the core keyword. The title sells the click; the H1 confirms the answer.
• Not the company tagline or a generic "Welcome".

H2 rules

• Four to twelve per page depending on length.
• 30 to 80 characters works well.
• Contains a secondary keyword or a clear topic from your keyword research.
• Phrased as a complete topic or question, not a single word.
• Should make sense in a table of contents.

H3 rules

• Nested inside an H2.
• Short. 20 to 60 characters.
• Covers a single sub-point.
• Not used to emphasise quotes or testimonials (use <blockquote> for that).
• Not used to make text bigger (use CSS for that).

Headings that win featured snippets

Google extracts featured snippets by matching the user's query against your H2 and H3 wording, then pulling the paragraph or list directly underneath. If you want to win position zero, your H2 has to be phrased the way someone would search.

Three patterns we use:

1. Question H2 followed by a 40-to-60-word answer paragraph. "What is the cost of an emergency callout?" followed by a clean two-sentence answer. Google quotes the paragraph directly into the snippet box.
2. Numbered list H2 with a list immediately below. "Five signs of a dangerous powerpoint" followed by exactly five numbered points. Google pulls the list into a numbered-list snippet.
3. Definition H2 with a single-sentence definition. "What is RCD protection?" followed by one tight sentence. Google highlights that sentence in the SERP.

The trick is matching the wording the searcher used. If they typed "what is" then your H2 should start "What is". If they typed "how to" then your H2 should start "How to". Mimic the phrasing. Boring but effective.

Common mistakes (and how to fix them)

How to audit an existing site's headings

Three-step audit, ten minutes per page:

1. Install a heading-tree browser extension (HeadingsMap for Chrome and Firefox, free). It shows the entire H1-H6 outline as a sidebar. Broken structure jumps out instantly.
2. Look for skipped levels. Any H3 without an H2 parent. Any H1 that is missing. Any page with multiple H1s.
3. Read only the headings. If the page topic is unclear from headings alone, the tree needs work.

On a 100-page site this is a half-day job. The wins are usually visible in Search Console within six to eight weeks because cleaner headings open the door to featured snippets and lift CTR on existing rankings.

Tools and checklists

1. HeadingsMap browser extension. Free. Shows the full heading tree of any page in a sidebar. Indispensable for auditing.
2. Screaming Frog. Free up to 500 URLs. Configure the crawl to extract H1, H2 and H3. Sort for missing H1, multiple H1s, missing H2s.
3. WAVE (WebAIM). Free. The accessibility audit also flags heading-structure issues. Useful proof for clients who need an accessibility argument.
4. Google Search Console Performance report. Filter by impressions but no clicks. These are often pages where headings do not match the user's query.
5. Our free SEO audit tool. Flags missing H1, duplicate H1, and missing heading hierarchy in one click.

A heading checklist before you publish

1. Exactly one H1 on the page.
2. H1 contains the primary keyword and reads naturally.
3. Every H3 has an H2 parent.
4. No levels skipped.
5. Headings make sense read in order without body copy.
6. At least one H2 phrased as the searcher's likely question.
7. No keyword stuffing in any heading.
8. Headings are styled by CSS, not by the tag chosen.

Perth and WA context

Four heading patterns we see go wrong on Perth sites, with the fix for each:

Trades. A typical Perth tradie site has the H1 set to the company name ("Smith's Electrical") on every page. The fix is page-specific H1s: "Emergency Electrician Perth" on the emergency page, "Switchboard Upgrades Joondalup" on the switchboard page, "About Smith's Electrical" only on the about page. The brand goes in the title tag and the H2, not the H1 on every URL. For trades-focused SEO context see trades SEO and SEO Joondalup.

Real estate. Real estate listing sites often use H2 for each property's address and H3 for the price, then H3 again for the agent name. The fix is to keep H2 for navigational sections of the page (e.g. "Featured listings", "Recently sold") and use <p> with appropriate CSS for individual listing cards. The listings themselves are data, not document structure.

Mining services. A common Pilbara-based pattern is dropping the entire services list as a flat sequence of H2s with no H3s underneath. The fix is grouping: H2 for service category ("Equipment hire"), H3 for each specific piece of equipment under it. See mining SEO and SEO Karratha for the broader patterns.

Healthcare and legal. Regulated industries often have compliance disclaimers in H4 or H5 tags to make them visually small. The fix is leaving them as plain paragraphs with appropriate CSS. The accessibility implications matter here: a screen reader user expects H4-H6 to be substantive content, not boilerplate fine print. See healthcare SEO and legal SEO.

For the broader on-page picture, the parent On-Page SEO pillar covers how heading work fits with title tags, content depth and internal linking. And the crawling, indexing and ranking guide covers what happens once Google has read your heading tree.