18 quintillion to 1. Got that? That’s 18,446,744,073,709,551,616 to 1.
The formula is simple. Take 64 games (which includes the play-in game) and factor one of two teams will win each game. So, you get 2 to the power of 64. (Multiply 2 by itself 64 times.)
So, when ESPN.com allows you to fill out up to 10 brackets for free, you’re helping your chances…but not by much.