What is an exacta bet in horse racing?

An exacta bet in horse racing, also known as a perfecta, is a type of wager that requires a bettor to select the top two finishers in a race in the order of finish.

Sounds simple in theory, but in practice, it is not.

If you bet a 1-6 exacta and the 6 wins and the 1 runs second, for instance, you lose.

To protect against that scenario, many horseplayers “box” horses. In this case, that means covering two combinations — 1-6 and 6-1 —  to ensure that they will win as long as the 1 and 6 finish first and second, no matter which one wins. (There’s also a bet known as a quinella that automatically covers both or all combinations in an exacta box.)

 Another popular strategy is to “key” a single runner to several other contenders.

Or you can get really and key one or two runners and box them with other horses you think could finish in the top two with their best effort.

To calculate the cost of such a ticket, figure the number of combinations included and multiply that by the base bet. That’s very simple with a $1 exacta box using two horses, which costs $2 (1×2=2). The math gets a little more complicated as you add more horses: A $1 exacta box using four horses, for example, costs $12: 1 (amount of base bet) x 4 (number of horses in the bet) x 3 (number of horses in the bet, minus 1)=12.

There are numerous online calculators that will do the heavy lifting to determine the cost of a given ticket, but you can also enter your selections on online wagering websites and determine the cost that way. Read more about strategies in horse racing and check out these U.S. online horse wagering sites to learn more.