I'm giving away one of the ways to calculate keyword density (in case one wants to know how?). All you need to do is count the number of times you repeated the keywords in total and divide it by the total number of words and finally multiply by 100. If anybody knows an easier way (for instance if there are any WP plugins to carry this out), please do share it with us!
I think this formula is good enough - (Nkr * Nwp / Tkn) * 100, Where, NKR = how many times you repeated a specific keyword Nwp= Nwp is the number of words in the phrase Tkn = the total words in the analyzed text