Im using Yoast SEO on wordpress. It tells me i have 20 keywords on the page while from what i can see, there is only6 in the actual content. it seems to include image names, alt tags, and keywords in link address. Meanwhile Seobook and other keyword density checkers all have there own results What is the best keyword density checker? and do image names, alt tags, and keywords in links count ?
Keyword Density is not important as long as you are not stuffing the page full of them. Just use them naturally throughout your text and you have nothing to worry about. I would not stress over different sites reporting different density numbers. http://www.webpronews.com/matt-cutts-talks-keyword-density-2011-12