THE PEOPLE. THE STORIES. THE IMPACT.Biographies & estimated net worth
PeoplespediaLIVES WORTH KNOWINGAn encyclopedia of remarkable lives
,

Bill Gates Biography: Microsoft Co-Founder, Philanthropist and Tech Billionaire

Daniel Reed
Bill Gates headshot

Bill Gates Biography: Microsoft Co-Founder, Philanthropist and Tech Billionaire

Bill Gates biography: Bill Gates is an American entrepreneur and philanthropist who co-founded Microsoft in 1975 and built it into the world’s dominant software company before turning to global health and development through the Gates Foundation. Born in Seattle on 28 October 1955, he became the world’s youngest self-made billionaire at 31 and was the world’s richest person for 18 of the 24 years between 1995 and 2017.

Quick facts

  • Full name: William Henry Gates III
  • Born: 28 October 1955, Seattle, Washington, USA
  • Nationality: American
  • Occupation: Entrepreneur, philanthropist, technology adviser to Microsoft
  • Known for: Co-founding Microsoft; the Gates Foundation; the Giving Pledge
  • Education: Lakeside School, Seattle; Harvard University (1973–1975, did not graduate)
  • Spouse: Melinda French Gates (married 1994; divorced 2021)
  • Children: Jennifer, Rory and Phoebe Gates
  • Books: The Road Ahead (1995), How to Avoid a Climate Disaster (2021), Source Code (2025)
  • Honours: Presidential Medal of Freedom (2016); Knight Commander of the Order of the British Empire (2005); Padma Bhushan (2015)

Early life and education

William Henry Gates III was born on 28 October 1955 in Seattle, Washington, the only son of William H. Gates Sr., a lawyer, and Mary Maxwell Gates, a banker and civic leader. At 13 he enrolled at Lakeside School in Seattle, where he met Paul Allen — his future Microsoft co-founder — and wrote his first program, tic-tac-toe, on the school’s Teletype terminal.

Gates entered Harvard University in the autumn of 1973, taking mathematics and graduate-level computer science, and meeting Steve Ballmer, who would later succeed him as Microsoft’s chief executive. He left in 1975, after two years, without a degree, to build a software company with Allen — the arrival of the personal computer, he has said, was too large an opportunity to wait for graduation.

Founding Microsoft

The trigger was the January 1975 issue of Popular Electronics, which featured the MITS Altair 8800, one of the first personal computers. Gates and Allen wrote a BASIC interpreter for the machine, and MITS agreed to distribute it as Altair BASIC. They set up their partnership — first called “Micro-Soft” — in Albuquerque, New Mexico, and the trade name Microsoft was officially registered in New Mexico on 26 November 1976.

The deal that made Microsoft’s fortune came in 1980, when IBM approached the young company for software for its upcoming personal computer. Microsoft bought 86-DOS from Seattle Computer Products and sold it as PC DOS (MS-DOS). The IBM PC launched on 12 August 1981, and Microsoft kept the right to license MS-DOS to other makers — the foundation of its dominance of personal computing. Windows 1.0 followed on 20 November 1985. Microsoft went public in March 1986, and in 1987, at 31, Gates became the world’s then-youngest self-made billionaire, with a net worth of $1.25 billion according to Forbes.

From chief executive to philanthropist

Gates ran Microsoft as chief executive for 25 years, until January 2000, when Steve Ballmer succeeded him. He became chief software architect until 2008, remained chairman until February 2014, when Satya Nadella became chief executive and Gates became his technology adviser — a role he still holds — and resigned from the board in March 2020 to devote more time to philanthropy.

That second career was already well under way. In 2000 he and his then-wife Melinda founded the Bill & Melinda Gates Foundation, now the world’s largest private charitable organisation, focused on global health, poverty alleviation and education. In 2010 Gates and Warren Buffett founded the Giving Pledge, whose signatories commit to giving at least half their wealth to philanthropy.

The foundation changed shape after the couple’s divorce, finalised on 2 August 2021 after 27 years of marriage. Melinda French Gates resigned as co-chair on 13 May 2024, and the organisation was renamed the Gates Foundation, with Bill Gates as sole chair; under their separation agreement she received an additional $12.5 billion for her own charitable work. On 8 May 2025 Gates announced the foundation would spend more than $200 billion over the next 20 years and close permanently on 31 December 2045, saying: “I will give away virtually all my wealth through the Gates Foundation over the next 20 years.” The foundation’s endowment was reported at $92 billion as of 30 June 2026.

Outside the foundation, Gates chairs Cascade Investment, his personal investment company, and backs energy ventures including TerraPower (nuclear) and Breakthrough Energy (clean-energy innovation). He has written five books, most recently the memoir Source Code: My Beginnings (4 February 2025).

The climate memo — and the 2026 reassessment

Gates’s most debated public intervention of recent years came on 28 October 2025, days before the COP30 climate conference in Belém, Brazil, when he published a memo on his GatesNotes site titled “Three Tough Truths About Climate”. Its three arguments were that climate change is serious but will not end civilisation; that temperature is not the best measure of climate progress; and that health and prosperity are the best defence against climate change. “Although climate change will have serious consequences, particularly for people in the poorest countries, it will not lead to humanity’s demise,” he wrote. He argued for judging success by human welfare rather than temperature alone, for driving the “Green Premium” — the extra cost of clean technologies — to zero, and for not cutting health and development funding to pay for emissions cuts.

The memo split opinion: climate scientists and environmental groups accused Gates of downplaying the danger and creating a false choice between cutting emissions and improving lives, while others called his focus on human welfare a necessary corrective. A year on, in November 2026, a retrospective argued his case had gained ground among policymakers — and searches for Bill Gates topped Google Trends in the United Kingdom on 13 November 2026, driven by the renewed debate. Gates has not abandoned climate work: he wrote the 2021 book How to Avoid a Climate Disaster and continues to fund climate innovation through Breakthrough Energy. The memo argued for reprioritisation, not withdrawal.

Personal life

Gates married Melinda French, a former Microsoft product manager, in Hawaii in 1994. They announced their split in May 2021; the divorce was finalised on 2 August 2021. They have three children: Jennifer Katharine Gates, born 26 April 1996; Rory John Gates, born 23 May 1999; and Phoebe Adele Gates, born 14 September 2002. Gates has said his children will each inherit “less than 1%” of his fortune, with nearly all of his wealth going to philanthropy. His honours include the Presidential Medal of Freedom, awarded jointly with Melinda in 2016, a knighthood (Knight Commander of the Order of the British Empire) in 2005, and India’s Padma Bhushan in 2015.

Net worth snapshot

As of November 2026, Bill Gates’s net worth is estimated at roughly $115–122 billion — Forbes put it at about $121.2 billion, ranking him around 17th richest in the world, while Bloomberg’s estimate was lower, at about $116 billion. The fortune now rests mainly on his Cascade Investment holdings rather than Microsoft shares, of which he owns about 1% or less, and it is shrinking deliberately as he gives it away through the Gates Foundation.

Frequently asked questions

How old is Bill Gates?

Bill Gates was born on 28 October 1955 in Seattle, Washington, making him 71 years old as of November 2026.

How did Bill Gates start Microsoft?

Gates co-founded Microsoft with his childhood friend Paul Allen in 1975, after they wrote a BASIC interpreter for the MITS Altair 8800 personal computer. The company began in Albuquerque, New Mexico, and its breakthrough came with MS-DOS for the IBM PC in 1981.

When did Bill Gates step down as Microsoft CEO?

Gates stepped down as chief executive in January 2000, succeeded by Steve Ballmer. He remained chief software architect until 2008 and chairman until February 2014, and resigned from the Microsoft board in March 2020.

What is the Gates Foundation?

The Gates Foundation, founded in 2000 as the Bill & Melinda Gates Foundation, is the world’s largest private charitable organisation, focused on global health, poverty alleviation and education. In May 2025 Gates announced it would spend more than $200 billion over 20 years and close permanently on 31 December 2045.

What did Bill Gates say about climate change?

In a memo published on 28 October 2025, “Three Tough Truths About Climate”, Gates argued that climate change will not end civilisation, that temperature is not the best measure of climate progress, and that health and prosperity are the best defence against it. The memo was widely debated, and a year later, in November 2026, commentary revisiting it drove renewed public interest.

Sources