A measure of prominent keywords that appear in the content of a page. The keyword density is the percentage of times a keyword or phrase appears on a web page compared to the total number of words on the page.

Keyword density is always considered to be important to search engine optimisation.  However, as search engine algorithms differ for each search engine and the algorithms are not advised, it is difficult to predict the optimum keyword density for all search engines. As a general rule, we recommend a value of between  3 and 5% excluding stop words as an optimum keyword density.