Header Tags
Header tags - H1 through H6 - do two things simultaneously. They help the person reading your page navigate it quickly without reading every word. And they help Google understand what your page covers and how the different sections relate to each other.
Neither benefit requires anything complex. It requires using the right tag in the right place, consistently.
What each tag does
Think of your page as a book. The H1 is the title - there is one per page, it defines the main topic, and everything else is subordinate to it. The H2 tags are chapter headings - they divide the page into its main sections. H3 tags are subheadings within those sections. H4 and below exist for deeply nested content and are rarely needed on standard pages.
When a reader lands on your page, they do not read from top to bottom. They scan the headings first to decide whether the content is what they were looking for and which section is most relevant to them. When Google crawls your page, it reads the heading structure to build a model of what the page covers and how well it covers it.
The H1 tag
Every page should have exactly one H1 tag. It should clearly state the main topic of the page, include your primary keyword naturally, and match what the searcher expects to find after clicking your title tag in search results.
According to data cited by Twenty Over Ten, 80% of first-page Google results include an H1 tag. Not having one does not guarantee a ranking penalty, but its presence is standard practice among pages that rank. The Moz Ranking Factors study found a positive correlation between including the target keyword in the H1 and ranking higher - not because the tag carries enormous weight on its own, but because it is a clear, unambiguous signal to Google about the page's primary topic.
John Mueller of Google has confirmed this directly: "We do use H tags to understand the structure of the text on a page better." The H1 is the most important of those signals.
The H1 and title tag do not need to be identical - and often should not be. The title tag is optimised for the SERP: concise, keyword-forward, designed to earn a click. The H1 is optimised for the reader who has already clicked: it can be slightly longer, more descriptive, and written more naturally as a heading.
H2 and H3 tags
H2 tags divide the page into its main sections. Each H2 should cover a distinct aspect of the main topic. If someone read only your H1 and your H2s, they should understand the entire structure and scope of the page.
H3 tags break an H2 section down further when a section becomes long enough to warrant internal organisation. Use them when they genuinely help the reader navigate - not as decoration, and not just to add more heading-level keywords to the page.
The rule on hierarchy: never skip levels. An H3 must follow an H2 - it cannot jump directly from an H1. An H4 must follow an H3. Breaking the hierarchy confuses screen readers and signals poor content structure to Google.
Keywords in headings
Including your primary keyword in the H1 is best practice. Including related secondary keywords and question-based variants naturally in H2 and H3 tags has two benefits: it helps Google understand the full topic coverage of the page, and it increases the page's chances of appearing in featured snippets.
Featured snippets are frequently pulled from heading-and-paragraph combinations - a question-style H2 or H3 followed by a clear, concise answer in the paragraph below it is the exact structure Google uses when generating list and paragraph snippets. If you want to rank in a featured snippet position, structured headings that mirror how someone would phrase the question are a direct route there.
Do not stuff headings with keywords. A heading should read naturally to a human. Keyword stuffing in H tags is a pattern Google recognises and does not reward.
Accessibility
Heading structure is not just an SEO consideration. Screen readers used by people with visual impairments navigate pages by heading structure. When headings are correctly nested - H1 then H2 then H3, without skipping levels - screen readers can announce each heading level and allow users to jump between sections.
A page with a broken or absent heading hierarchy is not just weak SEO. It is a poor experience for a meaningful portion of your audience. Getting the structure right serves both.
The practical check
Install the Ahrefs SEO Toolbar browser extension (free). Open any page on your site. Under On-Page, it shows the full heading structure in order. You can see at a glance whether your H1 is present, whether H2s follow it logically, and whether any levels have been skipped. Run this check on your most important pages - homepage, service pages, key blog posts - and fix any structural issues before moving on to other on-page work.
Next: Content optimisation