It happens, sometimes because of a bad website configuration, one or several of our pages have duplicate h1 tag on them. An accident which goes against Google’s guidelines but which can nevertheless make us wonder about the good ranking of a page.
Yes or no duplicate h1 tag will impact, negatively, the rankings of your page ?
What does Google say about H1 tag?
Before we get into whether it’s bad to have 2 H1 tags on the same page, let’s recontextualise things a bit. The main reason to have an H1 tag on a page is to structure the content of that page. Just as the pages of a book can be structured into chapters to give the reader a logical and increasing understanding of the story.
Google itself makes this clear
Use heading tags to structure your content hierarchically—for example, <h1>, <h2>, and <h3> in HTML, or #, ##, and ### in Markdown.
https://developers.google.com/style/headings
Therefore, the H1 tag can be considered as the chapter of the page because it is supposed to represent the topic matter. The rest of the Hn tags (h2, h3, h4, h5, h6 are there to structure the text in depth).
Google also recommends, and this is quite wise, that there is only one H1 tag on a page. You should also be careful with the construction of your site, especially if you use a cms, as the theme you use may automatically introduce an H1. Thus, by creating a page and integrating the title yourself, you would unintentionally create a second tag.
Ensure that each page in your project includes a unique level-1 heading. In some publishing systems, a level-1 heading might be generated automatically based on a page title that you supply
https://developers.google.com/style/headings
Why avoid duplicate h1 tag ?
If a duplicate H1 on the same page is to be avoided it is mainly for the quality of the crawl and the semantic understanding by the search engine of your page.
Indeed, the Internet user will not see the duplicate in question, he will be able to see the titles of a page but will not be able (unless he is an SEO) to check if it is several h1 or h2 etc…
On the other hand, the search engine robots will only see this, so to speak. This will mislead them in their analysis of the page and its content. Being faced with two h1s, especially if they are written differently, will result in confusion during the crawl.
What is the right h1? Which title should be taken into account because it better represents the text?
These are the kinds of questions that the engine will have difficulty in answering.
What are the risks of having duplicate h1s?
Nothing serious I assure you. You will not be penalized or warned in this way. On the other hand, the page or pages that will be affected by this duplication could have more difficulty in being positioned.