William Henry Gates III is an American businessman and philanthropist. A pioneer of the microcomputer revolution of the 1970s and 1980s, he co-founded the software company Microsoft in 1975 with his childhood friend Paul Allen. Gates became the world's then-youngest billionaire in 1987, at age 31. This followed Microsoft's initial public offering in the previous year and subsequent stock increase. Forbes magazine ranked him as the world's wealthiest person for 18 out of 24 years between 1995 and 2017, including 13 years consecutively from 1995 to 2007. Gates became the first centibillionaire in 1999, when his net worth briefly surpassed US$100 billion. According to Forbes, as of May 2025, his net worth stood at US$115.1 billion, making him the thirteenth-richest individual in the world.
Born and raised in Seattle, Washington, Gates was privately educated at Lakeside School, where he befriended Allen and developed his computing interests. In 1973, he enrolled at Harvard University, where he took classes including Math 55 and graduate- level computer science courses, but he dropped out in 1975 to co-found and lead Microsoft.