Adsense calculator is one of the best online tools to calculate Adsense earning by using Daily page impressions, Page CTR (in percentage) and CPC which is presented by webmaster Tools. You are here so we can understand that you are Adsense user and you monetized your blog/website with Google Adsense. That's great!
Google Adsense is a program run by Google through which website publishers in the Google Network of content sites serve text, images, video or interactive media advertisements that are targeted to the site content and audience. These advertisements are administered, sorted and maintained by Google. (Source: Wikipedia)