This year, Warren Buffett promised a billion dollars to anyone who picks a perfect bracket. Unfortunately, the odds aren't in your favor—the chance of picking a perfect bracket if you pick every game at random is one in 9 quintillion (or 9,000,000,000,000,000,000).

But that's just a hypothetical bracket. What are the odds of your bracket? The interactive below lets you figure that out. Using the betting lines for each game and on each team's chances of the making the Final Four and winning the NCAA Championship, the graphic calculates the odds of every possible NCAA matchup—and every possible NCAA bracket.

As you make your picks, each pick is colored according to that team's odds in the previous matchup. A green team is a pick for a favorite and a red team is a pick for an underdog. Picks colored grey aren't included in the odds calculations because they don't have an oppenent yet.

Heavy underdog Slight underdog No opponent picked Slight favorite Heavy favorite

At the bottom of the bracket, the graph shows how each team contributes to your bracket's overall chances. The bigger a team's circle, the more your picks for that team lower your bracket's chances—at least in the eyes of the oddsmakers. Don't want to look up your picks? Check out these brackets!

All the favorites Dick Vitale Seth Davis U.S. News College Rankings The FiveThirtyEight bracket President Obama's bracket Average picks on ESPN Actual results

Click on teams to make your picks!