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Colony counting to estimate colony forming units (CFUs) is a standard microbiology procedure used for determining the number of viable microbes in a system. Typically this process is done manually, which is time consuming, tedious, and sometimes error prone. Alternate image analysis based systems are also time consuming. In this paper we develop and demonstrate a simpleandroid based automated colony counter, called Colonizer, also made freely available on Google Playstore. Our algorithm can also threshold and segment overlapping colonies and thus provide rapid, accurate counts across a wide range of colony densities (from 50-500 colonies/plate), for different microbes, using any android based phone or device.