Horse racing is a popular sport throughout the world. The sport consists of a number of horses, usually thoroughbred horses, ridden by jockeys racing around a track. Betting usually consists of wagering money on which horse will finish first; or in the first or second place; or in the first, second, or third place; known respectively as betting to win, betting to place, and betting to show.

Horse racing odds at a track are usually displayed on a large board, called the tote board. This board presents the horse racing odds in terms of the amount of money you will collect relative to how much you wager. For example, if the horse racing odds are given as 3:1 on a particular horse, this means that if you wager $1 for the horse to win, and it comes in first place, you will receive $3. Many tracks have a minimum bet of $2, so the tote board also often includes a number showing how much money you would receive on a $2 bet.

Horse racing odds displayed on the tote are determined by taking the amount of money that has been bet on a given horse and figuring out what percentage it is of the total money bet on all horses — minus a portion for the track’s take, usually between 10% and 20% of the total. For example, if $1,100 has been placed on all horses, and $375 has been placed on Our Horse to Win, and the track’s percentage is 15%, then we would use the following procedure to calculate the horse racing odds on our stallion: First, we would take out the track’s percentage by multiplying $1,100 by 0.85, winding up with $935. We then take our horse’s bets out of that total by subtracting $375 from $935, ending up with $560. Then, we divide the total remaining bet pool by the amount placed on our horse, so divide $560 by $375, winding up with $1.49. That gets rounded up to $1.50, and our final horse racing odds are 1.5:1, or 3:2.

At the beginning of the day, of course, no bets have yet been placed, and so the tote has no data to work from in calculating its horse racing odds. This problem is solved by using what is referred to as the morning line, which calculates the horse racing odds for each entrant based on educated guesses of how bettors will place their bets throughout the course of the day. The tote is then updated every 30 seconds throughout the day, until bets close before the race. It is important to know that payouts are based not on the horse racing odds displayed when you place your bet, but on the tote as it reads upon the closing of betting.