How Much Does Semantic HTML Structure Matter for SEO?

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I’ve been posting on the page semantic HTML markup several times previously:

While the benefits for accessibility and usability are quite clear, there has never been any real evidence that there really is any benefit for rankings. Does Google pay any attention to the HTML markup? Another great thread over at WebmasterWorld discusses how much SEO value can the page headings add.


  • We quite seldom see sites that use page headings correctly. Plenty of the sites on top of SERPs have completely screwed HTML markup – still Google seems to love them. So does Google really evaluates HTML semantic structure at all?
  • If Google still does pay attention to HTML markup, how does it treat multiple H1 tags on one page? How can Google tell which one of them is more important?


  • H1 must be used for some relevance signals – but it’s very much a secondary or “reinforcing” signal rather than a primary signal of relevance. There is no chance for Google to use it as a primary signal because in most cases HTML markup is misunderstood and misused: thus Google must be focusing on the relevance rather than the techncal knowledge of the webmaster.
  • The effect of the page HTML markup can be seen from search results snippets: for example, H2 heading often appears in a snippet “even though there are other mentions of the query term earlier (and even more frequently) on the page.”
  • Google may be evaluating the “HTML markup noise” when deciding if page headings should be taken into account: it may be paying more attention to the site HTML markup if it used consistently throughout the site and each page has unique HTML structure. Thus, if the site uses invalid HTML markup (e.g. multiple H1 tags, or one and the same headings on each page), the worst what must happen is that Google will just disregard the overall structure and give words used in heading no prominence. Again, Google is believed to put more emphasis on relevance than the HTML standards compliance.

My experiments?
I have been testing different theories but that’s too early to say anything. At my own blog I use several identical H1 headings on each and every page deliberately – and doing not bad for only the one that goes first in the source code. But again, this requires more testing and I will be sharing my findings in the future.

Ann Smarty

Ann Smarty

Brand amd Community Manager at Internet Marketing Ninjas
Ann Smarty is the blogger and community manager at Internet Marketing Ninjas. Ann's expertise in blogging and tools serve as a base for her writing,... Read Full Bio
Ann Smarty
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  • Barry Wise

    I’ve also noticed proper markup is certainly not a requirement for ranking. I’d be interested in how your tests pan out re: identical H1s.

  • Mario Andrade

    I believe that a simples combination of page title, description, keywords can do alot, mix it up with a couple of header titles (h1, h2) and keyword rich content, if you add a few links from the right places and voilá.

    I don’t believe that semantic html will affect the rankings.

    For example I often see websites using H1 3 or 4 times on the same page and rank well for those keywords although the html structure is not valid.

  • WebSite Design Orange County

    Since there are over 350 components to the Google Ranking Algorithm it is kind of hard to say that just because a site ranks well it is due to one or another factor(s).

    A site with incorrect semantics may do everything else right, in Google’s eyes, and rank well. So to run an actual test one should be sure to compare apples to apples.

  • Canvas Art

    I do believe that combination of title,keywords and description matters a lot than semantic html

  • Personal Throws

    i feel this strategy is followed by the search engines. First when search engine crawls it checks and gives the importance to the heading tags and the meta-description like title,keywords, description and then the remaining parts of the page

    and i don’t feel the semantics are not that much important considerably

  • Ann Smarty

    @Canvas Art, actually, I believe everything should be taken care of… but from what you listed, meta keywords are of least importance now…

    • Chris

      @Ann You hit the nail on the head: there is no SEO magic bullet, so doing everything you can to make your site for SEF should be done (in order of important of course). I would say creating quality content that people actually want to see if the most important, even more so than getting inbound links. Create the content and the links will come. Keywords are least important if you’re only optimizing for Google. Google ignores them completely and Matt Cutts has made that clear. But I know that least Yahoo still considers them.

  • Mike at Seo Web design services

    I don’t believe it effects your rankings and if it does it is not a huge factor.

    It is googles job to provide the most relevant info which it feels is best and wether someone uses the same header tags everywhere should not majorly effect their rankings.

  • Adam

    I’m quite certain Google simply checks for at most 1 H1 header, and any subset of H2-H6 headers (making sure they are nested correctly isn’t too hard to parse). If the site follows those rules then it will score better…it’s not too hard to do and is probably a reward to sites that utilize good HTML documentation practices.

  • Shalom Issenberg

    Coding a site well is good for many reasons, but has little to do with SEO.

  • Mike

    I’ve always pondered this same question. I spend a lot of time making sure everything is correct, when the sloppiest pages seem to do just as well. I think it comes down to control. I can make sure my pages are validated, so even if that gives me a half a percent boost, I will do it because I can. (Where I can’t control exactly how Google ranks)

  • Andrew Miller

    I agree with @Shalom and @Mike. Regardless of whether or not validated code will result in slightly higher rankings, why WOULDN’T somebody strive to build sites that follow basic web standards? They are standards for a reason, because it makes websites easier for humans to use (accessibility, UX, usability, etc). Take care of those things and much of the rest will take care of itself.

    I, too, will be interested in your test findings though.

  • Ken

    Using the free validation tool provided by the W3C is also helpful in making sure everything is kosher.

  • Gry

    I really believe that propper html structure of teh page can not affect the position of this page in Google search results signifficantly. But since it does not cost much to keep the pages structured well, why not to ?

  • Jarlo Solde

    This is just plain stupid.