According to the NCAA, 60 to 100 million brackets are filled out every March. Nobody has ever predicted one perfectly.

Predicting the winner of the Super Bowl or World Series ahead of the NFL or MLB season is a hugely impressive feat. In college basketball, predicting the next champion is equally as difficult. 

But that's not the main attraction of the tournament.

With March Madness set to return, tens of millions of brackets will be filled out as basketball fans try to correctly call the outcome of every match from each regional clash all the way up to the national championship game.

Below we're going to take a look at March Madness brackets, how they work, the chances of predicting one perfectly and the key things to consider before you make your picks.

What	2023 NCAAB Championship
When	Wednesday, March 15th - Monday, April 3rd, 2023
How to watch	TSN

What is a March Madness bracket?

Ahead of the NCAA Tournament, millions of people attempt to chart the path of every team, which sounds like a straightforward thing to do on paper.

The First Four – the play-in round that consists of four games – isn't included in your bracket. Instead, the bracket starts once the field has been whittled down to 64 teams after those opening four matches have been played.

The bracket is set up in a grid once the final seeding and tournament draw are finalized. You then pick a winner of each matchup round by round through to the championship game.

The volume of upsets at the tournament means it's an incredibly challenging thing to do, but that does slightly level the playing field and make brackets accessible to people with no college basketball knowledge.

What are the chances of predicting a perfect bracket?

To correctly predict the NCAA Tournament you would need to call the outcome of all 63 games played across the month. If each of those games is treated as a 50-50 coin-flip, the odds of producing a perfect bracket is one in 9,223,372,036,854,775,808 or 9.2 quintillion to one.

Of course, not every game will be so evenly split. Teams across the four regional paths are seeded 1-16, which can help inform your choices.

While many will pull predictions from thin air, there is a slight edge towards those who follow the sport. However, given that the chance of a perfect bracket is considered to be one in 120.2 billion for those that know the sport, it's far from an exact science.

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What is the closest anyone has come to a perfect bracket?

Given the odds of correctly calling the tournament game-by-game, it's not exactly a surprise that no one has ever managed to pull off a perfect bracket.

The closest anyone has officially gotten to a perfect bracket is 49 games, which happened in 2019. That bracket was busted in the Sweet 16, falling 14 games short of a remarkable achievement.

When the tournament returned in 2021 it was clear that long runs weren't a new trend. Upsets saw the last bracket fall in the 28th game, while no bracket survived past the first Friday in 2022.

Things to consider when putting together your bracket

The challenge of putting together a bracket is one of the most appealing things about March Madness, but here are a few things to consider before you try your own.

While the NCAAB Championship can be unpredictable, going with a 1-seed winner tends to be the best bet.

Since the tournament was expanded to 64 teams in 1985, 24 of the 37 national titles have been claimed by a 1-seed. That includes each of the last five winners, while only three of those 37 championships went to a team ranked worse than a 3-seed.

The trick is backing how many 1-seeds make it all the way to the Final Four. The tournament has only once seen all four make it through the regional rounds, while just twice have all of the top seeds fallen before the Final Four.

No less than 30 of the last 37 tournaments have seen either one or two 1-seeds make it to the last four, so that seems like a good starting point for your bracket.

You then need to identify some outsiders capable of a deep run. In eight of the last nine tournaments, a team seeded seventh or lower has made it to the Final Four.

In 2022, that almost included 15-seed St Peter's, with the Peacocks seeing their Cinderella run ended by 8-seed North Carolina in the Elite Eight.

As you can see, completing a perfect bracket basically requires you to call the biggest shocks before they happen.

Given that around 70 million brackets are busted each year, that's clearly an almost impossible thing to do. Despite that, it's hard to shake the hope of landing that one in 120 billion bracket.