"The ultimate test:" Warren Buffett says there is only one measure of a successful life.

There’s wealthy people, and then there’s Warren Buffett. The American investor is part of what’s known as the three-comma club. Take a look at his net-worth and you’ll see why: US$84,000,000,000.

From his first stock purchase at age 11, he’s built a mega-business that owns the likes of Duracell and US restaurant chain Dairy Queen, and earned him the title of third wealthiest person in the world (behind Amazon’s Jeff Bezos and Microsoft’s Bill Gates).

But a biography of Buffett reveals something surprising about the way the billionaire measures success.

As reported by CBS, The Snowball: Warren Buffett and the Business of Life recounts a speech the 88-year-old gave at the University of Georgia, in which he said:

“Basically, when you get to my age, you’ll really measure your success in life by how many of the people you want to have love you actually do love you.

“I know people who have a lot of money, and they get testimonial dinners and they get hospital wings named after them. But the truth is that nobody in the world loves them. If you get to my age in life and nobody thinks well of you, I don’t care how big your bank account is; your life is a disaster.

“That’s the ultimate test of how you have lived your life.”

Buffett has certainly been fortunate in that regard. He was married to his first wife, Susan, for 52 years until her death in 2004. Together they had three children: Susie, Howard and Peter.

Two years later, he married long-time companion Astrid Menks, who had lived with him since 1977 after being introduced by Susan. It was an unusual arrangement; the trio reportedly sent Christmas cards signed, “Warren, Susie and Astrid”.

“Unconventional is not a bad thing,” Buffett’s daughter, Susie, told The New York Times back in 2006. “More people should have unconventional marriages.”

Buffett's approach to money isn't exactly typical either. As the CEO of Berkshire Hathaway Inc., he has taken home the same annual salary for decades: $100,000 (AUD$140,000), Reuters reported.

He's also promised to give away over 99 per cent of his fortune, and according to Forbes has so far donated US$35 billion, much of it to the Bill and Melinda Gates Foundation.

He also lives in the same home in Nebraska that he purchased in 1958 for just US$31,500 (AU$43,000).

"If I could spend $100 million on a house that would make me a lot happier, I would do it," he told PBS. "But, for me, that's the happiest house in the world. And it's because it's got memories, and people come back."

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