"That depends on what you count as work," Zuckerberg said in response to a question about how many hours he works each day. "I spend most of my time thinking about how to connect the world and serve our community better, but a lot of that time isn't in our office or meeting with people or doing what you'd call real work."
"I take a lot of time just to read and think about things by myself," he added. "If you count the time I'm in the office, it's probably no more than 50-60 hours a week. But if you count all the time I'm focused on our mission, that's basically my whole life."
CEOs famously work long hours and have little time for their families. Though Zuckerberg works a much longer week than the average American, he seems to have struck a better work-life balance than most other heads of corporations.
Zuckerberg sets personal challenges for himself, including hunting all the meat that he eats, learning Mandarin and reading a new book every other week.