Normally it is assumed that search engine rankings will automatically improve once we insert keyword and related subset of word in the Meta tag of the pages in the web site. But truth is totally different story; you should know that only select few algorithms utilize keyword Meta tag for search engine optimization.

To sort out the problem most of the search engine optimization expert suggest using a SEO tool to find out the keyword density.

This tool will calculate the relevant keyword phrases along with the Meta tag from all the words present on a page of the web site. If certain phrase or keyword appears many times on a page, keyword density SEO tool will calculate the “keyword density” of that phrase or keyword.

The keyword density is defined as the ratio of phrase or keyword to the total number of words in the content of the page of the web site. Use of phrases in the keyword density analysis allows us to get input regarding density and proximity of the keywords in the content at the same time.
Most of the SEO professionals find an average range of 2 to 8 percent of keyword density as the optimum range of keyword density for all practical purposes. Major search engine keep changing their algorithm from time to time and SEO professional need to update them regarding these changes and their implications.

Higher density of keywords leads to stuffing, which may result in the branding as spasm by the search engine. So search engine optimization is more like a tight rope walk, keep the optimum balance of keyword density to make your efforts effective.