Remember: It's a matter of WHEN, not IF, your March Madness bracket is BUSTED. There's never been a perfect one . . . and the chances of you doing it is somewhere between 1-in-46 billion and 1-in-9.2 QUINTILLION. (That's with 17 zeroes) Or more specifically, 1-in-9,223,372,036,854,775,808.
For context, there are roughly 7.5 quintillion grains of sand on Earth. Imagine being given ONE chance to pick a single, specific grain of sand somewhere on the planet . . . and nailing it. Your odds of doing THAT are 23% better than completing a perfect bracket.
BUT, it's more complicated than that. That math assumes that each team has a 50/50 chance of winning. Obviously, that's not the case. If you adjust the math to represent the historical probability of how teams in each round do based on their seeding . . . the odds of getting a perfect ballot are reduced to 1-in-46 billion. Or specifically, 1-in-46,576,549,017.
That's a better stat . . . but it's still not perfect, because the tournament doesn’t follow a formula, and historically roughly 20% of the 63 games are UPSETS, where the winning team is at least two seeds worse than the losing team.
It's impossible to quantify basketball knowledge in probability, but a third method simply looks at how good people are at filling out brackets.
In the many millions of brackets that were filed with the NCAA over the past five years, the average person gets 42 of 63 games correct, which is 66.7%.
If you extrapolated that success rate out, it'd give you odds of 1-in-120 billion, or specifically, 1-in-120,246,505,336. That's still a LOT. If you filled out a completely unique bracket EVERY SECOND of every day, you'd be guaranteed to have a perfect ballot . . . after 3,813 years.
Interesting fact: The NCAA has run a bracket challenge for EIGHT years now . . . and the best they've seen is 54 of 63 correct guesses. And the best START they've seen is 39 correct picks before the bracket was busted.