What is keyword density and should you optimise for it in 2021?

Does keyword density still exist?

In this blog, I will be discussing the common SEO technique of optimising for a thing known as keyword density: a once very effective content writing tactic to catapult your pages to the first page of search results. We will learn exactly what keyword density is, if it’s still effective in 2021 and how you can modernise the understanding of keyword density for SEO.

What is keyword density?

Firstly, we must understand what keyword density is. Keyword density simply means how much a specific keyword or key phrase is mentioned within a piece of content. During the early days of Google’s algorithm and page ranking, the algorithm would only have a basic understanding of how relevant a page is to a search term by seeing how many times that search term is mentioned within the page. With such a basic and easily manipulated understanding of relevancy, people would begin using a groundbreaking and highly advanced SEO optimisation technique: spam the keyword in your content so Google thinks your content is far more relevant than your competitors.

Is keyword density still a factor in SEO?

Thankfully, Google’s many algorithms (Search is handled by 200+ different algorithms!) have managed to come to a better understanding as to what is relevant to a search term, and more importantly what is a high-quality result. The old tactics of keyword density is no longer viable or effective in SEO. Even Google, way back in 2011, cleared this up in a YouTube video by Matt Cutts, saying:

So if you think that you can just say, I’m going to have 14.5% keyword density, or 7%, or 77%, and that will mean I’ll rank number one, that’s really not the case. That’s not the way that search engine rankings work. So the way that modern search engines, or at least Google, are built is that the first time you mention a word — hey, that’s pretty interesting. It’s about that word. The next time you mention that word, it’s still about that word. And once you start to mention it a whole lot, it really doesn’t help that much more. There’s diminishing returns. It’s just an incremental benefit, but it’s really not that large. And then what you’ll find is if you continue to repeat stuff over and over again, then you’re in danger of getting into keyword stuffing, or gibberish and those kinds of things. So the first one or two times you mention a word, then that might help with your ranking, absolutely. But just because you can say it seven or eight times, that doesn’t mean that it will necessarily help your rankings.

LSI Keywords

Today, Google takes a more holistic approach to understanding the relevancy of your content. When you are optimising your content for keywords, it is no longer about how many times you can stuff your keyword into the content, or the density of your specific phrase. With LSI (Latent Semantic Indexing) Google will use related words, topics and synonyms to understand the relevancy of your content. For example, if you were to optimise your blog about an iPhone 7 you need to consider related phrases and topics such as: Apple, mobile phones, smartphones, technical hardware, iOS etc. This will make your content more relevant to your keyword and more high-quality than people who decide to stuff their content with “iPhone 7” as much as they can.

With Latent Semantic Indexing, it is completely possible for an authoritative website with high-quality content to rank for search terms and keywords that are not exactly mentioned in the content. For example: a freelance web designer may rank for search terms such as web design company, web design agency etc, even if those exact terms are not included in the content. This is because Google understands that a freelance website designer is still relevant to an agency or company that offers web design as a service – although they are still two different things. Another example for the locals is that Google can understand that the word “Scouse” is the same as Liverpool. If a local business is optimising their pages for Liverpool services, their website will also rank well for search terms that include “Scouse” instead of Liverpool. Again, “Scouse” will not be mentioned in the content, but Google understands that “Scouse” is highly relevant to Liverpool, which is mentioned in the content.


Keyword density as it was once understood and used, is no longer an option for modern SEO. In 2021, relevancy is understood by your content’s overall topic relevance, including the use of related keywords, subjects and synonyms as opposed to targeting a density for an exact match keyword.