European vs American Roulette: The Zero That Changes the Odds
Why one wheel has a house edge of 2.70% and the other 5.26%, with the arithmetic shown.
· 5 min read
Count the pockets
A European wheel has 37 pockets: numbers 1 to 36 and a single zero. An American wheel has 38, because it adds a double zero. A straight bet on one number pays 35 to 1 on both wheels, so the extra pocket on the American wheel lowers your chance without raising the payout.
The arithmetic
Because every standard roulette bet is built to give this same edge, it applies whether you play red or black, a column or a single number.
- European: you win 1 time in 37 and are paid 35, so the expected return per unit is 36 / 37, a house edge of 1 / 37, or 2.70 percent.
- American: you win 1 time in 38 and are paid 35, so the return is 36 / 38, a house edge of 2 / 38, or 5.26 percent.
La Partage, En Prison and other rule variants
Some European tables return half of an even-money bet when the ball lands on zero, a rule often called La Partage, or hold the bet for the next spin under En Prison. These rules reduce the edge on even-money bets. Rules vary by provider, so check the game information screen rather than assuming.
What the edge means in practice
Using assumed figures for illustration: 5 units a spin and 30 spins an hour for two hours comes to 300 units wagered. That is an expected cost of about 8 units on a European wheel and about 16 units on an American one. Short sessions can end far from the average either way.
Choosing a wheel
If a casino offers both, the European wheel is the better value. Compare them side by side in the calculator, or read about each live roulette format.