The odds listed in the race program are the “morning line” odds. These are the odds placed on the horses by the track’s handicapper when the race program is published, before the wagering starts. At the track, the odds will be posted on the tote board before the race; they change up until post time, depending on how customers are betting on each horse in the race.
The horse that customers have bet the most money on is called the "favourite". This horse will have the lowest odds.
The "longshots" have the least amount of money wagered on them and therefore have the highest odds. The racetrack handles the money, keeps a percentage (called a “take-out”) and calculates the horses' odds based on the amount of money wagered on each horse. The remaining money is then paid back to the players who have winning tickets.
Win odds on the tote board are displayed based on $1.00 unless otherwise noted. A "3" displayed next to a horse's number indicates that the horse is 3-1. An example of an exception to this general rule is when "5/2" is shown. The tote board does not show decimals, therefore, 5/2 odds means that the odds on a horse are 5 divided by 2, or 2.5-1. Win payoffs are calculated based on a $2.00 wager because at most tracks this is the minimum bet. Example #1: A horse that wins at 5-1 will return $5.00 for every $1.00 wagered. If you had placed the minimum bet of $2 on that horse to win, your payoff will be: $10 (5 x 1 x $2) + your original bet of $2 – for a total of $12.
Example #2: A horse that wins at 9-2 will return $4.50 for every $1.00 wagered. If you had placed the minimum bet of $2 on that horse to win, your payoff will be: $9.00 (4.50 x 1 x $2) + your original bet of $2 – for a total of $11.
Generally, payoffs are as follows, based on a $2 wager: