You hear about keyword density a lot in article marketing and SEO. What that means is you take the number of times you use your targeted keyword and divide it by the number of total number of words in your content. So if you write a 1,000 word article and your keyword is “lunch money”, which you use 15 times in the article, then your keyword density is .015%. Article marketing gurus like to say that the optimal keyword density is somewhere between 2%-6%.
There are several things wrong with this theory. Firstly, natural writing without focusing on keyword usage will fall somewhere between that range anyway for well-written content. Secondly, search engines now recognize synonyms for certain words and can ascertain what your content is about on the basis on those synonyms, the use of which will make your writing less staid and robotic. Thirdly, there are other factors involved in ranking web pages in the search engines. Keyword usage is only one factor, and it isn’t even the most important factor. It is important, but it isn’t the most important.
Search engines rank web pages according to many factors – last count, there are more than 150 ranking factors. One of the most important ranking factors – more important than actual keyword usage – is your page headline. I’m not talking about your meta title. I mean the verbiage in your headline, which should be written as an h1 tag and should use your primary keyword. Subheads are also important. Other on-page factors should be considered and some off-page factors like link relevance, anchor text of inbound links, etc. Note that these factors involving keyword usage have nothing to do with keyword density. They are ranking factors involving weight of importance, much like a college professors grading scheme.
Keyword density is a false measure of on-page SEO. You’d be better off learning how to make your pages work using as many of the ranking factors as possible.