The casino odds in a roulette game are set by 35 to 1. This means that when you win the house pays you $35 and you get to keep your original $1 bet. The house edge is the amount the player loses on average to any bet made. If you bet on a single number in the European roulette game there is a probability of 1/37 that you win 35 times the bet, and a 36/37 chance that you will loose the bet. In European roulette the house edge is 2.70%. The green squares on the roulette wheel and on the table are the only house edge. When you place an outside bet you will always lose when 0 or 00 shows. The house also has an edge on inside bets where you have a 36 to 1 chance at winning a straight bet on a single number and the pay out is always set at 35 to 1.