Roulette Odds Calculator
Compare the true probability and expected return for standard European and American roulette bets.
Probability and payout are not the same
A straight-up number on a European wheel wins once in 37 possible outcomes, a probability of about 2.70%. The casino pays 35 units of profit plus the returned stake, not 36 units of profit. That difference creates the 2.70% house edge.
On an American wheel there are 38 pockets because both 0 and 00 are present. Standard payouts remain unchanged, so the house edge on most bets rises to 5.26%.
Expected value example
Place one unit on red in European roulette. Eighteen results win one unit and nineteen results lose one unit. Across all 37 equally likely pockets, the expected result is (18 − 19) / 37, or −1/37 of a unit. The same calculation applies to most standard wagers even though their volatility is different.
French tables offering La Partage or En Prison can reduce the edge on qualifying even-money wagers to approximately 1.35%. Always check the exact table rules.