Keyword Density is one of the famous SEO terms representing the ratio of times a particular keyword or keyword phrase has been used in the writing, compared to the whole document. In other words, it tells you how frequent a keyword is stated in the writing.
In the late ‘90s, keyword density was the main criteria search engines used to assess relevancy. The higher the keyword density meant the more the relevancy, up to a certain level (about 7 percent was the red line of search engine spamming).
But today, keyword density is just one of the side factors of relevancy measurement along with anchor text linking, domain’s age, popularity, visitors’ count, etc.
Although spamming is not totally defected by search engines, SEO experts often glance at keyword density to avoid over-optimization (keyword-stuffing) of their publications. Most of the article sites have a certain threshold of keyword density to announce an article as promotional, which neither search engines nor SEO companies like.
How Different Google and Yahoo Treat Keyword Density
Based on research presented on goRank.com, by comparing the results of more than 2000 keywords, the following secrets were revealed:
How Do I Measure a Key Phrase’s Density?
Using the famous keyword density formula (keyword occurrence ÷ total words x 100 percent), you can determine the percentage of a certain keyword’s density, but today there are some cool prefab SEO tools for this, called Keyword Density Tools, that enable you to measure a certain Web page’s keyword frequency or abundance. Some of these tools depict the results by a list of mostly used keywords and some others show a keyword cloud. WordPress especially presents a plug-in for your WordPress blogs for illustration of the keywords or tags cloud. This cloud consists of a mass of tiny and giant keywords where bigger words represent higher density.
What Do I Do to Decrease a Keyword’s Density?
Headings, repeated, bolded and italic words in a text will be counted as important by search engines. So a highly styled, excessively keyword-stuffed document is more likely to be punished by the search engines by dropping in page rank. You should never use excessive styling to highlight a keyword for search engines or readers. If your document shows a high frequency of a certain keyword, you can either use other forms of the word, or use its synonyms to decrease the frequency.
Note that excessively keyword-condensed documents will sound unreasonable when read by a real human and thus losing traffic will be minimum of the consequences of this malpractice, so keeping the keyword density between 3 to 7 percent by the optimizer will make it easy to use for Web users and search engines, and consequently result in better page ranking.