Bill Gates says he worked 80-hour weeks, 'Feared one mistake could ruin everything’

Microsoft co-founder Bill Gates has revealed that he used to work 80-hour weeks writing software for his company. Speaking to CNBC Make It, the 69-year-old said he continued working long hours for over a decade after becoming a billionaire because he still did not feel successful.

“I wouldn’t say that I felt comfortable that we were successful until about 1998 or so,” Gates said. This was 11 years after Microsoft went public. At the time, he was 31 and had just become the youngest billionaire in history, Forbes reported.

“That’s the first time I look back and say, ‘Okay, we are in a pretty good position here, and I understand why my competitors are so jealous that they think they need the Justice Department to help them out,’” he added, referring to antitrust lawsuits against Microsoft, as rivals and the US government accused the company of being a monopoly.

In his new memoir, Source Code, Gates shared how he regularly worked 80-hour weeks, coding software and worrying that any mistake could threaten Microsoft’s position in the booming personal computer market. At the time, Microsoft was the world’s most valuable public company, worth over $250 billion. Gates himself was the world’s richest person, with an estimated net worth of $58 billion.

“Not until the late-90s did I feel like, ‘Wow, we can even make a few mistakes and still be okay,’” Gates said. “I thought I was one mistake away from death until then. That was just my mentality.”

Today, Microsoft is valued at over $3 trillion, while Gates’ net worth is estimated at $165 billion, according to Bloomberg.