How Many Different March Madness Combinations Are There?

The March Madness field will be announced on Sunday, March 16 at 8 PM EDT. That's when we’ll learn the 68 teams that will take part in the most popular multi-week tournament in U.S. sports. At the end, after 67 games are played, we’ll know the champion of college basketball.

In 2024, according to Statista, close to 40 million adults completed an NCAA College Basketball Tournament bracket. With four play-in games, and 16 teams in four regions playing over three weeks, that’s a lot of bounce passes, tip-ins, and buzzer beaters.

A hoops fan who fills out a bracket knows how hard it is to decide between high seeds, low seeds, favorites, underdogs, alma maters and so on. In fact, it’s so complicated that no one has ever filled out a perfect bracket in the roughly 30 years that such things have been tracked.

Just getting all four Final Four teams is a challenge. Indeed, the March Madness bracket challenge is one of the toughest mathematical puzzles in sports.

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Odds Against Filling Out a Perfect March Madness Bracket

How difficult is it to pick March Madness games with a high success rate? It’s hard.

It’s even tougher to be perfect. So tough that in 2014, one of the world’s richest men, Warren Buffet, offered $1 billion to anyone who successfully filled out a perfect bracket before the NCAA tournament began.

What are the odds of someone filling out a perfect bracket, picking all 63 game winners of the 64-team bracket challenge? Mathematicians tell us it’s one in 9.2 quintillion. Never heard of quintillion? You're not alone. It’s not a number that’s needed very often. Here’s what it looks like:

1,000,000,000,000,000,000

That’s a one followed by 18 zeros. That’s equal to a billion billions. To put that in perspective, Bill Gates, who is worth an estimated $135 billion, would need to get 875 million more billions just to have a quintillion. Or to illustrate it another way: famous former Beatle Paul McCartney is estimated to be worth $1 billion. The writer of Hey Jude would need to multiply his wealth by a billion just to get to quintillion.

A quintillion is a heckuva lot. And the odds of filling out that perfect March Madness bracket are 9.2 quintillion.

How Many Combinations of Brackets for the NCAA Basketball Tournament?

There are 9.2 quintillion possible bracket combinations for March Madness. As we stated above, the odds of picking a perfect bracket are 1 in 9.2 quintillion, which is a billion billions.

Amazingly, even in the U.S., where college basketball and the March Madness tourney is extremely popular, nowhere near enough brackets are filled out each year to come close to all the possibilities. The American Gaming Association estimates that 70 million brackets are filled out in the United States each year ahead of the tournament. That’s only 0.0000000000001 percent of the brackets that are possible.

A sports fan, even with help from all his friends and family, could never fill out the 9.2 quintillion brackets needed to cover every possibility.

Even if every man, woman, and child on the Earth filled out brackets, each person would be required to complete 1.2 billion brackets.

Want another way to picture the sheer magnitude of 9.2 quintillion? There are 36.1 million seconds in a year. That means it would take 292 billion years to get to 9.2 quintillion seconds. What will college basketball look like in 292 billion years? Somehow we’re glad we won’t be around to find out.

Yet another unfathomable way to view the problem of being correct in so many games is by the exponential number. For any two-game section of a first round bracket, the odds of getting perfect is 1 in 8. Fair enough. For an entire region (16 teams, 31 games in the region), it’s 1 in 32,768. Doesn’t sound bad, right? That’s far, far better odds than winning the lottery. But when you keep expanding the game size, you get exponential growth that’s hard for even our top-level primate brains to understand. Getting half the bracket correct (two regions, 32 teams, and 62 games) is 1 in 2,147,483,648. That’s 1 in about 2.1 billion. But when we extrapolate that to four regions, the entire 64-team bracket, and 63 games, we arrive at the 9.2 quintillion mentioned above.

Best March Madness Bracket Streak in Recent History

In 2019, a college hoops fan in Ohio successfully picked the first 49 games of the NCAA tournament. That means he was correct in all 32 first-round games, all 16 second-round games, and in the first game of the Sweet Sixteen.

How amazing was that feat? The man was the first person verified to have gotten his bracket to the Sweet 16 round without missing a pick. Bravo, Buckeye.

The Adjusted Odds for Picking a Perfect Bracket

In actuality, the odds for picking a perfect bracket are a little less than 9.2 quintillion. What? Does that mean this article is pointless? No. The mathematics, without outside factors, are accurate when it says 1 in 9.2 quintillion (add 17 zeros after the 2).

But each game is not like a coin flip. The March Madness tournament has favorites and underdogs. There are mismatches, especially in the first round. Only twice since the tournament went to 64 teams has a No. 16 seed defeated a No. 1 seed, for example. And the No. 2 seed has a win percentage of more than 90% against No. 15 seeds.

In 2016, a mathematician quoted on the website Five-Thirty-Eight used the probability odds of higher seeds typically winning matchups against lower seeds. He figured you can improve the chances of filling out a perfect bracket to 1 in 2.4 trillion.

That seems pretty easy, huh?

Where to Fill out Your March Madness Bracket

Here at Ball Is Life, we have you covered for March Madness and your brackets. Visit our March Madness home page to find everything you need about odds, Final Four predictions, and to download your own printable bracket.