Keyword density — also called keyword frequency — is the number of times a specific keyword appears on a webpage compared to the total word count. It’s often reported as a percentage or a ratio; the higher the value, the more your selected keyword appears on your page. Google & other search engines respond well to keyword density around 0.5%.
The caveat? You can’t simply “stuff” as many keywords as possible into your content & expect reliable results. This practice is called keyword stuffing & it’s a black-hat SEO practice that can lead to penalization & even full-on removal from the SERPs.
How do you calculate keyword density? The formula is straightforward: Divide the number of times a keyword is used on your page by the total number of words on the page.