Bill Gates, in full William Henry Gates III, (born October 28, 1955, Seattle, Washington, U.S.), American computer programmer and entrepreneur who cofounded Microsoft Corporation, the world’s largest personal-computer software company. Gates wrote his first software program at the age of 13. In high school he helped form a group of programmers who computerized their school’s payroll system and founded Traf-O-Data, a company that sold traffic-counting systems to local governments. In 1975 Gates, then a sophomore at Harvard University, joined his hometown friend Paul G. Allen to develop software for the first microcomputers. They began by adapting BASIC, a popular programming