You only need to take the number of times a keyword appears on your page and divide it by the text's total number of words. If your primary keyword appears five times and your blog post has 500 words (D= 5/500= 0.1), Done!  SEO marketers have created this keyword density per page formula that even a beginner can calculate for practical purposes. However, when thinking about analyzing keyword density, do not focus all your efforts on achieving a "perfect percentage" for how many keywords per website page. It is only a ratio indicator.  Instead, I recommend that the terms and meta keywords you want to integrate into your page are found in the text and read naturally. This is the secret to achieving a perfect density and not confusing our readers with forced phrases.