Start with the wheel, because the wheel decides the odds
You sit down, buy in, and the first thing you should do is look at the wheel itself. An American roulette wheel has 38 pockets. The numbers run from 0 to 36, and then there is one extra pocket marked 00. That second zero is not a cosmetic detail. It is the single biggest reason the odds on an American table differ from the odds on a European one, and it changes the price of every bet you can make.
The numbers are not arranged in numerical order around the wheel. They are distributed so that high and low, odd and even, and red and black alternate as evenly as the layout allows. The zero and double zero sit opposite each other, both in green pockets. The sequence around an American wheel is fixed, and knowing it does not help you predict where the ball will land. It is useful only for recognising the wheel type at a glance.
How a round proceeds
A round of roulette is a sequence of small, fixed steps. Understanding the sequence matters more than memorising the layout, because most procedural mistakes happen when a player acts at the wrong point in the sequence.
First, you buy in. You place cash or a casino card on the table, and the dealer exchanges it for roulette chips. These chips are often different from the chips used at other tables, and at many venues each player at the table receives a distinct colour so that bets do not get mixed together. You cannot take these chips to the cashier; they must be exchanged back at the roulette table.
Next comes the betting window. The dealer opens betting, and you place chips on the layout. You may place multiple bets on the same spin, and different players may bet on the same numbers. When the dealer calls an end to betting, usually with a phrase like "no more bets," the layout is closed. Any chip placed after that call is a late bet and will be returned or ruled invalid.
The dealer then spins the wheel in one direction and sends the ball travelling in the opposite direction around the outer track. When the ball loses momentum, it drops into one of the 38 pockets. The dealer places a marker on the winning number, clears the losing bets, and pays the winners. Only after the marker is removed does the next betting window open. A common beginner mistake is reaching for chips while the marker is still on the layout, or placing a bet before the dealer has opened the next round.
What the 38 pockets mean for each bet
Every bet in roulette pays according to the number of pockets it covers. The house edge comes from the difference between the payout and the true odds. On an American wheel, the double zero widens that difference on almost every bet.
Consider a straight-up bet on a single number. There are 38 equally likely pockets, so the true odds against winning are 37 to 1. The table pays 35 to 1. The gap between 37 to 1 and 35 to 1 is the house edge. On a European wheel with 37 pockets, the same bet faces true odds of 36 to 1 against, with the same 35 to 1 payout. The American wheel therefore holds a larger edge on the same wager.
The same principle applies to outside bets. A bet on red covers 18 of the 38 pockets. The two green pockets mean there are 20 pockets that are not red, so the bet loses more often than it wins. The payout is even money, 1 to 1. The gap between the 18 winning pockets and the 20 losing pockets is the house edge on that bet.
Not every bet on the same table carries the same edge. On an American wheel, a bet on the five-number combination covering 0, 00, 1, 2, and 3 carries a larger edge than most other bets, because it pays 6 to 1 while the true odds against it are 33 to 5. The table below compares the main bet categories.
| Bet | Pockets covered | Payout | What the extra zero does |
|---|---|---|---|
| Straight-up | 1 | 35 to 1 | True odds lengthen from 36 to 1 against to 37 to 1 against |
| Split | 2 | 17 to 1 | Same payout as European wheel, but one extra losing pocket |
| Street | 3 | 11 to 1 | Same payout as European wheel, but one extra losing pocket |
| Corner | 4 | 8 to 1 | Same payout as European wheel, but one extra losing pocket |
| Five-number (0, 00, 1, 2, 3) | 5 | 6 to 1 | Exists only on American wheels; carries a larger edge than other inside bets |
| Six-line | 6 | 5 to 1 | Same payout as European wheel, but one extra losing pocket |
| Red, black, odd, even, 1-18, 19-36 | 18 | 1 to 1 | Two green pockets instead of one, so the bet wins less often |
| Dozens and columns | 12 | 2 to 1 | Same payout as European wheel, but one extra losing pocket |
The table shows a pattern worth internalising. The double zero does not change the payout on most bets. It adds one more losing pocket. The payout stays the same while the true odds worsen, and that is precisely how the house edge grows.
American versus European: the comparison that matters
The question "how many numbers does an American roulette wheel have" usually comes from someone trying to choose between tables or understand why two roulette games look slightly different. The comparison is straightforward once you see the wheels side by side.
| Feature | American wheel | European wheel |
|---|---|---|
| Pockets | 38 | 37 |
| Zero pockets | 0 and 00 | 0 only |
| Effect on outside bets | Two green pockets lose on red, black, odd, even, high and low | One green pocket loses on those bets |
| Five-number bet available | Yes | No |
| House edge on equivalent bets | Higher | Lower |
Some American tables also use a different rule for even-money bets when the ball lands in zero, sometimes called a surrender or la partage variant. That rule returns part of the stake on a zero result and changes the effective edge on those specific bets. Whether a table offers it is printed in the table rules or posted at the wheel, and it is worth checking before you sit down, because it materially changes the cost of outside bets.
Where the numbers come from and what they do not tell you
The 38-pocket layout is a fixed physical fact. It does not change from spin to spin, and the wheel has no memory. A number that has not appeared for many spins is not more likely to appear on the next spin. Each pocket remains equally likely on every spin, assuming a fair wheel and a properly maintained mechanism. The ball does not owe anyone a result.
Roulette is a negative-expectation game. The house edge is built into the payout schedule, not into the sequence of outcomes. No betting pattern changes the number of pockets or the payout table. A player can choose which bets to make, how much to wager, and when to stop, and those choices determine the pace of play and the size of the swings. They do not change the edge on the bet itself.
If you want to know the exact house edge on a specific bet at a specific table, the information you need is the payout printed on the layout and the number of pockets on the wheel. The arithmetic is simple enough to do at the table. The payout is fixed and printed. The pocket count is fixed. The edge follows from those two facts.
FAQ
Why does an American roulette wheel have 38 numbers instead of 37?
The American layout adds a double zero pocket alongside the single zero. The numbers 1 through 36 are the same as on a European wheel. The extra zero pocket is the only structural difference, and it exists to give the house a larger edge on every bet that does not cover it.
Does the double zero change the payout on a straight-up bet?
No. A straight-up bet on a single number pays 35 to 1 on both American and European wheels. What changes is the true odds. On an American wheel there are 38 pockets, so the true odds against a single number are 37 to 1 rather than 36 to 1. The payout stays the same while the chance of losing increases.
Are all bets on an American wheel equally affected by the double zero?
No. The five-number bet covering 0, 00, 1, 2, and 3 exists only on American wheels and carries a larger edge than other inside bets. Outside bets such as red or black are affected because the two green pockets both count as losing results. Some tables offer a special rule on even-money bets when zero appears, which changes the effective edge on those bets specifically.
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