Roulette Rules & Odds: European vs. American vs. French

Roulette is the same game on every wheel except for one detail that matters more than any strategy: the number of zeros. A European wheel with one zero gives the house 2.70% on every bet. An American wheel with two zeros nearly doubles that to 5.26%. French rules on a single-zero wheel cut the even-money bets to 1.35%.

How a round works

1. Place bets. You put chips on the layout: on single numbers, groups of numbers, or outside areas such as red, odd or a dozen.
2. The spin. The dealer spins the wheel one way and the ball the other. Bets usually close shortly before the ball drops.
3. The result. The ball lands in one numbered pocket. The dealer marks it, clears losing bets and pays winners.

Numbers 1 to 36 are split between red and black. The zero pockets are green. That's the whole game: one pocket, chosen at random, every spin.

The three wheels compared

The bets and payouts are the same on all three wheels. Only the zeros, and what happens to even-money bets when one hits, differ.

Telling them apart takes two seconds: look for a 00 pocket on the wheel and a 00 box at the top of the betting layout. If it's there, you're at an American table, and every bet costs nearly twice as much as it would one table over.

Every bet, its payout and its chance of winning

Inside bets go on the numbers themselves. Outside bets cover large groups along the edge of the layout.

Notice that zero isn't red, black, odd or even. When the ball lands on a green pocket, every even-money bet loses (unless French rules apply).

Why the edge is the same on almost every bet

Every payout is set as if the wheel had only 36 pockets. A bet covering n numbers pays:

One number pays 36 − 1 = 35:1. Twelve numbers pay 3 − 1 = 2:1. The extra green pockets are never paid for, and that gap is the house edge.

The exception is the American five-number bet on 0, 00, 1, 2 and 3. It pays 6:1, but a fair price for five numbers out of 38 would be 6.6:1. Per $1: 5 × $6 − 33 × $1 = −$3 over 38 spins, so EV = −3/38 ≈ −7.89%. It's the one bet on the layout to avoid entirely.

French rules: La Partage and En Prison

French tables use a single-zero wheel and add a consolation rule for even-money bets when zero hits:

• La Partage: you get half of your even-money bet back.
• En Prison: your bet stays on the table, locked, for the next spin. If it wins then, you get it back; if it loses, it's gone.

The rule applies only to even-money bets. A straight-up bet at a French table still carries 2.70%.

Same edge, different ride

If every bet on a European wheel costs 2.70%, what separates them is volatility: how bumpy the ride feels on the way to that average.

Picture 37 spins at $10 each in which the ball lands in every pocket exactly once, a perfectly average run:

• Red every spin: 18 wins of $10 and 19 losses (18 blacks plus the zero). Net −$10.
• The same number every spin: one win of $350 and 36 losses of $10. Net −$10.

Both lose $10, which is 2.70% of the $370 wagered. Real sessions are never that tidy, though. The red bettor's results tend to cluster near the average, while the straight-up bettor swings wildly.

The chance that a single number misses all 37 spins is (36/37) to the 37th power ≈ 36.3%. So about one session in three, the straight-up bettor loses the full $370. When the number does hit twice, the same bettor walks away well ahead. Pick a bet for the ride you prefer, not for better odds, because there aren't any.

What each wheel costs per hour

A live table typically runs about 30 to 40 spins an hour. Take 35 spins at $10 a spin, or $350 wagered:

• European: $350 × 2.70% ≈ $9.46 expected loss per hour.
• American: $350 × 5.26% ≈ $18.42 per hour.
• French, even-money bets only: $350 × 1.35% ≈ $4.73 per hour.

Same game, same bets, and one option costs nearly four times as much as another. Try your own bet sizes with the house edge calculator.

Streaks, systems and Monte Carlo, 1913

In 1913, at a casino in Monte Carlo, black came up 26 times in a row. It's the classic story of a streak that makes red feel "due." Yet on every one of those spins, red's chance stayed exactly what it always is: 18/37. The odds of a run like that are on the order of one in tens of millions, but rare doesn't mean the wheel remembers.

That belief is the gambler's fallacy, and it powers most roulette systems. The Martingale (double after every loss) is the best known. Since every bet carries a negative expected value, any sequence of bets does too. A progression only reshapes the losses into many small wins and occasional large losses; see the Martingale math for the full calculation.

The bottom line

Roulette's math is refreshingly simple: every bet pays as if the zeros weren't there, and the zeros are the house edge. Your one meaningful decision is the wheel. Single-zero beats double-zero, and French rules on even-money bets beat both.

No bet selection or progression changes the edge. Pick a budget, expect to pay roughly the edge on everything you wager, and treat any win as luck, not strategy.