What Year Was Microsoft Founded and Who Were Its Founders: The Full Origin Story

Microsoft was founded in 1975, and its founders were Bill Gates and Paul Allen. The company began as a partnership in Albuquerque, New Mexico, on April 4, 1975, and was incorporated in Washington State on November 26, 1976. A third early participant, Gates's Harvard classmate Monte Davidoff, wrote the floating-point math routines for the first product but was never a founder or equity partner.

The Microcomputer Trigger and the BASIC Bet

The founding mechanism was a specific technical opportunity, not a general ambition. The January 1975 issue of Popular Electronics featured the Altair 8800, a mail-order microcomputer kit built around Intel's 8080 processor. Gates and Allen recognized that the Altair had no practical programming language for general users.

Allen wrote a simulator for the 8080 on a Harvard PDP-10 so the pair could develop and test code before touching real hardware. Gates wrote the core interpreter, and Davidoff contributed the floating-point routines. The result was Altair BASIC, which the pair licensed to Micro Instrumentation and Telemetry Systems, the Altair's manufacturer.

The counterintuitive detail: the famous "Open Letter to Hobbyists" in 1976, in which Gates complained that most Altair BASIC users had not paid, came after the software was already circulating. The business model preceded the moral argument. Microsoft's founding logic was that software could be a separately sold product, not a free byproduct of hardware.

Timeline: From Partnership to Corporation

The New Mexico period matters because it anchors the legal founding date. The 1975 partnership established the entity; the 1976 incorporation created the corporate structure. Both dates are correct depending on what a question is asking.

Quantified Context: How Small the Start Was

Microsoft's first-year revenue is often reported in the low tens of thousands of dollars, and the original partnership split was 64 percent Gates, 36 percent Allen. The Albuquerque operation had a handful of employees. The company's first office was a small suite, not a campus.

For scale, the 1986 IPO valued Microsoft at roughly USD 500-600 million at offering, and Gates's stake made him a paper millionaire many times over. Within a decade the company's market value exceeded USD 100 billion. The gap between the founding scale and the eventual scale is the reason the founding story is worth learning: the mechanism, not the myth, explains the trajectory.

Allen's later equity was diluted to roughly 28 percent by the time of incorporation and further reduced afterward. He left Microsoft in 1983 after a Hodgkin's lymphoma diagnosis, though he remained a board member for years. The shareholder structure explains why the "two founders" answer is clean legally even though a third programmer contributed code.

Edge Cases: The Founders Question Has Real Ambiguity

Monte Davidoff wrote the floating-point routines for Altair BASIC in 1975 and was paid a flat fee, not equity. He is a contributor, not a founder. The name "Micro-Soft" was hyphenated in early documents; the hyphen was dropped by the time of incorporation. The April 4, 1975 partnership and the November 26, 1976 incorporation produce two defensible "founding dates" for different purposes. Allen's departure in 1983 does not change founder status; founders are defined by the act of founding, not tenure. Gates's role changed dramatically after 2000 and 2008, but that also does not affect founder status. Microsoft's later acquisitions, including LinkedIn and Activision Blizzard, created no new founders of Microsoft itself.

The practical takeaway: if a source names only Gates and Allen, it is correct for founders. If it names Davidoff as a founder, it is conflating early contributors with equity founders.

Misconceptions Worth Correcting

The most common error is treating the 1975 date as the incorporation date. The partnership date is April 4, 1975; the Washington incorporation is November 26, 1976. A related error is naming Steve Ballmer as a founder. Ballmer joined in 1980 as employee number 30 and became the first business manager, but he was not a founder.

Another misconception is that Microsoft began in a garage. The company started in Albuquerque offices tied to MITS, then moved to Bellevue in 1979. The garage narrative belongs to other tech origin stories and gets retrofitted onto Microsoft because it is a convenient shorthand.

A professional caveat: founding dates are legal facts subject to corporate records, not folklore. When in doubt, cite the state incorporation filing and the partnership agreement rather than secondary retellings.

Practical Actions for Verifying the Record

If you need the founding facts for research, a citation, or a quiz answer, work from primary sources in this order:

Check the Washington Secretary of State corporate registration for the November 26, 1976 incorporation date. Consult Microsoft's own corporate history pages and annual reports for the 1975 partnership date. Use contemporaneous coverage, such as the 1975 Popular Electronics Altair article, for the technical trigger. Treat later memoirs and interviews as narrative, not legal record, and note them as such. For founder status, require an equity or partnership stake, not merely paid work on a product. Reconcile any conflicting dates by asking whether the source means partnership, incorporation, or first revenue.

Applied correctly, these steps produce a defensible one-sentence answer: Microsoft was founded in 1975 by Bill Gates and Paul Allen, with incorporation following in 1976.

Limitations and What the Record Cannot Tell You

The record is strong on dates and named founders because corporate filings and contemporaneous publications survive. It is weaker on exact early revenue, the precise division of labor between Gates and Allen on specific code, and the degree to which Davidoff's contribution was understood at the time. Memoir accounts from Gates and Allen differ in emphasis, which is normal for recollections written decades later.

The founding story also cannot tell you why Microsoft succeeded at scale. That outcome depended on the 1980 IBM contract, licensing strategy, and distribution, none of which were predetermined in 1975. Treat the founding as a necessary but not sufficient cause.

For ordinary low-stakes use, none of this requires a disclaimer. The answer to the keyword question is stable and well-documented: 1975, Gates and Allen.