Why the Kentucky Derby generates big betting payoffs

The Kentucky Derby (G1) at Churchill Downs is considered one of the best betting races of the year. The reason? Big payoffs. And the reason for the big payoffs? Simple mathematics.

Two factors make the Kentucky Derby more likely than your average horse race to generate enticing betting payoffs. One is the amount of money in the betting pools. Let’s say superfecta wagering is offered in a nondescript race at a small racetrack. If the superfecta pool features only $1,000 in bets after takeout, there’s no way it can pay more than $1,000, even if longshots dominate and only a single horseplayer hits the bet.

The Kentucky Derby, on the other hand, draws millions of dollars in wagers. In 2023, the superfecta pool exceeded $13.7 million. Theoretically, if only a single bettor hit the Kentucky Derby superfecta, they would cash a ticket worth millions upon millions of dollars.

That’s where the second factor comes into play: field size. With a 20-horse maximum field size, the Kentucky Derby features many more horses (and many more possible outcomes) than a typical horse race, making it harder for bettors to assemble winning tickets.

The math is striking. Compare the 20-horse Derby field to a 10-horse field in an ordinary race. In the Derby, it’s twice as hard to hit a win bet since there are twice as many horses to choose from. Now consider the exacta, which requires you to select the top two finishers in order. In a 10-horse field, there are 90 possible exacta outcomes. In a 20-horse Derby field, the number of possibilities shoots up to 380.

The numbers get crazier as the bets get harder. The trifecta requires selecting the top three finishers in order. In a 10-horse field, there are 720 possible trifecta outcomes. In a 20-horse Derby, there are 6,840. The superfecta involves choosing the top four finishers in correct order; with 10 horses there are 5,040 possible outcomes, while with 20 horses there are 116,280. How about the Super High 5? Selecting the top five finishers in a 10-horse field is hard enough with 30,240 possibilities, but the 20-horse Derby field takes it to a whole different level with a staggering 1,860,480 possible outcomes.

The large field and huge betting pools combine to yield the big payoffs the Kentucky Derby is known for. Even when the outcome is fairly predictable, the payoffs can be generous; when favored Justify beat fifth choice Good Magic and third choice Audible to the finish line in 2018, the $1 trifecta returned a healthy $141.40.

And when longshots strike? The results can be life-changing. In 2022, a single bettor hit the $1 Super High 5 with 80-1 longshot Rich Strike on top, and the payoff was $741,018.90. In 2005, when Giacomo and Closing Argument finished 1-2 at odds of 50-1 and 71-1, the $1 superfecta paid $864,253.50.

It’s no wonder why the Kentucky Derby is such an awesome betting race.