This search engine optimization (SEO) guide explains the different types of header tags in SEO.
Below, you’ll find a list of all the header tag types with their terminology and definitions so you can understand how they apply to SEO.
There’s also a section with additional resources that explain more about the fundamentals of header tags to help you create a better search engine optimization strategy.

Table of Contents
Types of Header Tags In SEO
H1 Tag for the Main SEO Topic
The first type of header tag in SEO is the H1 tag. This is the highest-level header you can put on a page and is one of the first HTML elements that search engine crawlers use to analyze the main SEO topic for the content.
The H1 header tag is typically coded in HTML to be the page title or post title on a website or blog for users to read. Therefore, out of all the headings you can optimize for SEO, the H1 tag has the most SEO weight and is the location you’ll want to put your primary keyword for increased relevancy and rankings in the search engine results pages (SERPs).
Note: The resource section at the end of this page includes a link to a guide that teaches you how to optimize all of the header tags correctly for SEO. Make sure to read that page for a deeper level of understanding for improved search engine optimization.
H2 Tag for Subheading Keywords
Another kind of header tag is the H2 tag. It serves as the second-level heading in HTML that defines the subsections of the main H1 header.
H2 subheading tags carry significant weight for on-page SEO because the H2 tags reinforce the key topics for the page and search engine crawlers use this information to index the content for relevant search queries.
A good practice for H2 tag optimization is to include your primary and secondary keywords in their own H2 subheadings without repeating them more than once. The primary SEO keyword can go in the last H2 tag on the page to reaffirm the core SEO topic; however, repeating the same exact match keywords in multiple H2 headers does not offer much improvement for on-page SEO and can be classified as keyword stuffing if overdone.
H3 Tag for Subtopic Headers
H3 tags are also an example of header tags in SEO. Unlike the previous two types of headings, the H3 tag doesn’t carry a significant amount of weight in terms of search engine performance.
H3 tags are a third-level header, which causes search engine crawlers to treat keywords in these HTML locations with less importance because they’re often less reflective of the main SEO topics for the page.
However, it’s still a good practice to optimize the H3 tags for SEO by including partial match keyword phrases, keyword variations, synonyms, and semantically-related words to boost the topical relevance of the content.
Just be careful not to add the same exact match keywords that you’re using in the H1 and H2 tags to avoid over-optimization. H3 tags should be only used for describing the subtopics of the associated H2 header tags, which is why having the same keywords you’re targeting for SEO in the H3 subheadings could cause an over-optimization penalty.
H4 Tag for Subheader Clarity
The next header tag type is the H4 tag which is typically only used when for adding more clarity to an H3 subtopic that requires an extra level of detail for the user to understand the information.
Although some SEO experts have performed independent tests that indicate the H4 tag has some effect on keyword rankings in the SERPs, this header is at such a low level in the HTML hierarchical structure that its impact on the search engine rankings is minimal at best.
Therefore, if you don’t need an H4 tag to help with readability or comprehension for the user, then you can safely ignore these header tags for SEO purposes.
H5 and H6 Tags for Complex SEO Structures
The H5 to H6 are less common header tag examples in SEO because these subheadings have no impact on search engine rankings.
H5 and H6 tags are also not seen very frequently on web pages because most subtopics do not need to go five or six levels deep for the reader. Content that requires H5 or H6 header tags would typically include a high degree of complexity, which is often only found in very technical documents.
Also, because these the H5 and H6 header tags are so low in the HTML informational structure for the page, they’re often ignored by search engine crawlers for SEO keyword relevance. Therefore, you can—and should—skip using these subheading tags when writing SEO-friendly content.
Learn More About Header Tags
The links below explain more about header tags and how to use them correctly for better search engine optimization. Use these resources to expand your knowledge on the subject.
Header Tag Types for SEO Summary
I hope you enjoyed this guide explaining the types of header tags in SEO.
As you discovered, there are many different header tag types in the field of search engine optimization. That’s why it’s important to understand specific terminology and definitions of each kind of header tag so you know how they can be applied best to your SEO strategy.
