Definition
Roulette
Also known as Roulette Wheel, European Roulette, American Roulette
By Abhinav VasudevanReviewed Editorial policy
In short
Roulette is a wheel game where you bet on where a ball will land. The house edge comes entirely from the zero pockets: 2.70% on a single-zero wheel, 5.26% on a double-zero one.
Roulette is the clearest illustration of a house edge in any casino. The wheel has 37 or 38 pockets, the payouts are calculated as though it had 36, and the difference is the entire margin.
The three wheels
| Wheel | Pockets | House edge |
|---|---|---|
| European (single zero) | 37 | 2.70% |
| American (double zero) | 38 | 5.26% |
| Triple zero | 39 | 7.69% |
Every bet on a given wheel carries the same edge, with one exception. The five-number bet on an American wheel (0, 00, 1, 2, 3) is worse at 7.89%.
Never play an American wheel when a European one is available. It is the same game costing nearly twice as much, and the choice is usually available in the same room or the same lobby.
Why the edge is what it is
A single number on a European wheel wins 1 time in 37. Fair odds would be 36 to 1. The casino pays 35 to 1.
Over 37 spins of £1 you expect one win returning £36, against £37 staked. The £1 shortfall is 2.70% of turnover. Every other bet on the table is constructed from the same arithmetic and produces the same figure.
Bet types
Inside bets cover specific numbers and pay from 35:1 down to 5:1. Higher variance, same edge.
Outside bets cover large groups, red/black, odd/even, dozens, columns, and pay 1:1 or 2:1. Lower variance, same edge.
The choice between them changes the shape of your session, not its expected cost.
The rules that genuinely help
French roulette applies La Partage or En Prison to even-money bets when zero lands. Either rule halves the edge on those bets to 1.35%, which makes red/black on a French table one of the better bets in a casino.
These rules are not available on every table and are worth seeking out specifically.
Systems
Martingale, Fibonacci, D’Alembert, Labouchère. None of them work, and the reason is structural rather than empirical. Each spin is independent, so no sequence of bets changes the expected value of the next one. A negative-expectation bet repeated in any pattern remains negative.
What systems change is the distribution: many small wins and rare large losses, or the reverse. The average is fixed by the wheel.
Common questions
What is the house edge in roulette?
2.70% on a single-zero European wheel, 5.26% on an American double-zero wheel and 7.69% on triple-zero. Never play American when European is available, since it is the same game costing nearly twice as much.
Do roulette systems work?
No. Martingale, Fibonacci, D'Alembert and Labouchère all fail for the same structural reason: each spin is independent, so no sequence of bets changes the expected value of the next one. Systems change the distribution, not the average.
Which roulette bet has the best odds?
Even-money outside bets on a French table with La Partage or En Prison, where the edge halves to 1.35%. Without those rules every bet on a European wheel carries exactly 2.70%.