The House Edge in Roulette

The house gains its edge over the player because of the appearance of a zero and a double-zero on American roulette wheels. European wheels have only one zero, giving the player a better chance of winning.

Casino Edge Affect the Payoff

Let's calculate how the casino's edge affects the payoff of a wager on our favorite number, seventeen.

We have already calculated the probability of the number showing, which is 1 out of 38 or 1 to 38.

If the house did not have an edge over the player, the correct payout for winning the wager would be the real odds against winning the bet, which is 37 to 1. However, the house gains an edge by shortchanging the player on the payoff of a winning bet and only pays the wager at 35 to 1. The house keeps 2 out of the 38 numbers for itself. These numbers are the zero and double zero.