Keyword Density refers to the number of times a keyword has been referenced in your content.
As an example, if a keyword has been mentioned 4 times in a 100-word article, that keyword will have a keyword density of 4%. It’s relatively straight forward.
There have been lots of speculations in the SEO industry that having a keyword density of 2-4% is best-practice and is the best way forward without over-optimising your content. Some SEO’s believe that keyword density doesn’t play a part in the ranking algorithms and it doesn’t matter how many times you reference a specific keyword, as long as the content is relevant. There are lots of theories.
Matt Cutts spoke about keyword density back in 2011 and mentioned that it’s not the way search engines work and that we shouldn’t be trying to hit a specific percentage.
In order to calculate such density, it can be done manually, however, a lot of SEO’s tend to use the following tools:
I personally try and include some mentions of my target keyword, so I try and stick to the 2-4% keyword density rule, but that’s just me.