What is an exacta bet? Very simply an "exacta" is when two horses in a race come in first and second after the race is over. An "exacta bet" is placed before the race. It is structured by you so you think you have the best chance to win the bet. Structuring an exacta bet can be quite simple or it can be much more elaborate.
Let's take the simplest case. Suppose you handicap a race and come up with a very strong opinion that horse 3 will win and horse 8 will come in second. A straight exacta bet would be placed as (for example) $2 exacta 3 with 8 or more conveniently as $2 exacta 3/8. Depending on how strong your opinion is it could be a $5 or $10 or $20 or $50 exacta bet.
Next, suppose you handicap a race and come up with a very strong opinion that horse 2 will win. However, you find three other horses that you think could come in second, say, horses 1,6 and 9. You would then structure your bet as $2 exacta 2/1,6,9. (We will use $2 in our example.) Three possible outcomes would be a winner with this bet: 2 with 1, 2 with 6, or 2 with 9.
Let's take our examples a step further. If you think that two horses (say 1,3) could win and three other horses (say 1,3,5,7,9) could place then you would structure your bet as (assuming a $2 bet) $2 exacta 1,3/1,3,5,7,9. Any of these outcomes would win the bet: 1/3, 1/5, 1/7, 1/9, 3/1, 3/5, 3/7, 3/9. Since there are 8 possibilities, we multiply by $2 and the cost of the bet would be $16.
Another way to look at structuring an exacta bet would be what is called an exacta box. Let's say, after you handicap a race, that three horses look to be contendors to win or place. Suppose 2,9,6 are these three horses. A $1 exacta box would be $1 exacta box 2,6,9. To win this bet here are the winning combinations: 2/9, 2/6, 9/6, 9/2, 6/2, 6/9. The cost would be (6 x $1 =) $6.
The last example I'll use will be one that involves all horses in the race. Let's illustrate this bet with a one million dollar Grade I race. A race like this usually has very strong (top level) horses in the race, so strong that any of the horses in the race could potentially and realistically win or come in second. To get coverage plus have a chance for hitting a large exacta payoff here is the way you could structure your bet. Say you like the 5 horse to either win or place. You would make two exacta bets. Assuming 8 horses in the race then a $1 exacta 5/ALL (ALL = all 8 horses) would win when the 5 horse wins and any of the other horses come in second. It will cost $7. (Note that the higher the odds of the second horse the larger the exacta payoff would be.) To cover the possibility that the 5 horse might place, a second bet (sometimes called a hedge bet) would be $1 exacta ALL/5 and it too would cost $7. Together you have $14 invested in these two bets.
I have given you several exacta bet examples to get you started. There are numerous other possibilities. Remember to always factor in the cost of the bet versus the potential payoff. Also always stay within the "bankroll" you go to the track with. Here is an article on my blog that talks about the bankroll.
http://handicapbet.blogspot.com/2010/07/betting-strategies.html
For a more advanced article on the exacta bet go to this link:
http://handicapbet.blogspot.com/2008/02/exacta-betting-using-tote-analysis.html
To use the 'exotic wager calculator' go to
http://handicapbet.blogspot.com/2007/12/exotic-bets-exotic-wager-calculator.html
