The wheel that starts the whole article
A player sitting down at an American roulette table is looking at a wheel with 38 pockets. Thirty-six of them carry the numbers 1 through 36, split evenly between red and black. The other two pockets are green: the single zero and the double zero. That is the entire answer to the question, but the question only matters because of what those two green pockets do to the odds on every other bet on the table.
The green pockets are not neutral decoration. They are the mechanism by which the house edge on an American wheel is built. When a player bets on red, there are 18 red pockets that win and 18 black pockets that lose. The two green pockets also lose. The player is therefore not facing an even proposition, even though red and black look like a coin flip. The wheel has 38 pockets, and only 18 of them pay on a red bet.
Reading the wheel before the first spin
American roulette uses a wheel with numbers arranged in a fixed sequence, alternating red and black around the circumference, with the zero and double zero sitting opposite each other. The table layout mirrors the wheel, showing all 38 numbers plus the outside betting areas. A player buys in at the table, receives roulette chips in a colour specific to that player, and places bets on the layout before the dealer calls an end to betting.
The sequence of a round is short. Bets go down, the dealer spins the wheel in one direction and sends the ball around the track in the other, and the ball loses momentum and drops into a pocket. The dealer marks the winning number on the layout, clears losing bets, and pays winners. Then the next round begins. The green pockets are in play on every spin, on every bet, whether the player thinks about them or not.
What the two green pockets do to each bet
The house edge on American roulette comes directly from the gap between the payout a bet offers and the true odds of that bet winning. The two green pockets create that gap. A straight-up bet on a single number pays 35 to 1, but the true odds against hitting that number on an American wheel are 37 to 1, because there are 38 pockets and only one winning number. The difference between 35 to 1 and 37 to 1 is where the operator's advantage lives.
The same arithmetic applies to every bet on the layout. Red or black pays even money, but the chance of winning is 18 in 38, not 18 in 36. Odd or even, high or low, the same. The green pockets are the reason a player who bets red on every spin of an American wheel can expect to lose more often than they win, even though the payout is advertised as even money.
| Wheel type | Total pockets | Green pockets | Effect on even-money bets |
|---|---|---|---|
| American | 38 | 2 (zero and double zero) | 18 winning pockets out of 38, so the house edge is higher |
| European | 37 | 1 (single zero only) | 18 winning pockets out of 37, so the house edge is lower |
The European wheel has the same red and black numbers and the same single zero, but no double zero. That one missing pocket changes the arithmetic on every bet. On a European wheel, an even-money bet has 18 winning pockets out of 37. On an American wheel, the same bet has 18 winning pockets out of 38. The player loses the same number of ways but faces one more losing pocket. The American layout is the more expensive version of the same game.
Inside bets, outside bets, and the same arithmetic underneath
Roulette bets are conventionally divided into inside and outside bets. Inside bets are placed on the numbered part of the layout: straight-up on one number, split across two, street across three, corner across four, six-line across six. Outside bets sit around the edges: red or black, odd or even, high or low, dozens, columns. The distinction is about payout size and hit frequency, not about escaping the green pockets. Every bet on the table is priced against the same 38-pocket wheel.
A player who wants a bet that hits often will choose an outside bet like red or black. A player who wants a larger payout will choose an inside bet. Neither choice changes the fundamental structure. The outside bets pay less because they win more often; the inside bets pay more because they win less often. The green pockets sit outside all of it, collecting on every losing spin regardless of which bet produced the loss.
Procedural mistakes that cost more than the house edge
The most common mistake at an American roulette table is not checking which wheel is in front of the player. Some venues offer both American and European layouts, and a player who assumes the wheel has one zero when it has two is playing against a different house edge than they think. The wheel itself is the first thing to read: count the green pockets before the first bet goes down.
A second mistake is treating the green pockets as a bet like any other. A straight-up bet on zero or double zero pays 35 to 1, the same as any other single number. The payout is not higher because the pocket is green. The bet is just another single-number wager with the same odds as a bet on 17 or 29. Players sometimes load the zeros thinking they are special; they are not, except that they are the pockets that make every other bet worse.
A third mistake is chasing even-money bets after a run of losses. A player who has seen red hit five times in a row and bets black because black is "due" is making a bet with the same 18-in-38 chance it had before the run started. The wheel has no memory, and the green pockets do not care what happened on the last spin. The sequence of past outcomes changes nothing about the next spin.
Where the house edge number comes from
The house edge on any roulette bet can be worked out from the wheel itself. For an even-money bet on an American wheel, the player wins 18 times in 38 and loses 20 times in 38. The difference between winning and losing outcomes, expressed as a share of all outcomes, is the house edge. The same calculation on a European wheel produces a smaller number because the denominator is 37 instead of 38 and the player loses 19 times instead of 20.
This is why the green pocket count is not a piece of trivia. It is the single number that determines how expensive the game is to play. A player who understands that an American wheel has two green pockets and a European wheel has one already understands more about the game's economics than most people at the table.
FAQ
Do the green numbers pay the same as other numbers?
Yes. A straight-up bet on zero or double zero pays 35 to 1, the same as a straight-up bet on any other single number on the layout. The green pockets are not higher-paying bets; they are simply the pockets that create the house edge on all other bets.
Can I bet on both zero and double zero at the same time?
Yes. On an American layout the zero and double zero sit next to each other on the wheel, and a split bet covering both is available. It pays 17 to 1, the same as any other split bet covering two numbers, and it wins if either green pocket hits.
Why does the American wheel have two green pockets when the European wheel has one?
The double zero was added to the American layout as a historical variation, and it remains in use at many venues. The practical effect is that every bet on an American wheel faces one additional losing pocket compared with the same bet on a European wheel, which raises the house edge across the entire table.
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