Divided out, this gives you a 48.65 percent or 47.37 percent chance of winning. For example, an even money bet on red has odds of 18/37 or 18/38. To calculate your complete odds, you need to multiply the payout by the initial odds. The greater the odds of winning roulette bets, the less the payout the lower the odds of winning roulette bets, the higher the payout. It will help to see the page on roulette odds and understanding how to play roulette. If you were betting on a corner, your odds would be 4/37 or 4/38. For example, if you bet on one number, the odds would be 1/37 or 1/38 depending on the wheel type (American or European). Therefore, the odds of the ball landing on your number or color are your bet divided by 37 or 38. (The European wheel has one green slot labeled “zero” and the American roulette wheel has two greens: zero and double zero). On an American roulette wheel, there are 38 slots on the wheel. The standard odds of winning roulette are calculated by dividing the number of winning numbers by the number of possible numbers.