In this formula, "Number of Conversions" refers to the number of desired actions taken by visitors on your website, such as making a purchase or filling out a form. "Number of Visitors" refers to the total number of people who visit your website during a specific time period. Conversion rate optimization (CRO) is the process of improving the percentage of website visitors who take a desired action on your website. The desired action can vary depending on the goals of your website, but common examples include making a purchase, filling out a form, subscribing to a newsletter, or downloading a file.