Microsoft was founded in 1975.
Bill Gates and Paul Allen established Microsoft on April 4, 1975, in Albuquerque, New Mexico. They initially focused on software for the Altair 8800, an early microcomputer produced by Micro Instrumentation and Telemetry Systems. Their Altair BASIC interpreter helped establish the company's software business.
Microsoft later became closely associated with the IBM PC after supplying an operating system called MS-DOS. Windows followed as a graphical operating-system family and eventually became one of the world's dominant desktop platforms. The company expanded into productivity software, cloud computing, gaming, and professional networking.
The founding date is sometimes confused with Microsoft's 1986 stock-market listing or with the 1985 release of the first version of Windows. Those are later milestones. Microsoft became a public company in 1986, while its corporate story began more than a decade earlier.