The extra pocket changes every bet on the layout
When you sit down at a roulette table and look at the wheel, the first thing that tells you which game you are playing is whether there is a double zero. A wheel with 38 slots carries the numbers 0 through 36 plus a 00. That second green pocket is not a cosmetic difference. It is the single structural fact that separates this layout from the 37-slot single-zero wheel, and it alters the arithmetic of every wager you can place.
Roulette numbers run 0-36 on both layouts. The 38-slot wheel adds the double zero, giving the wheel 38 equally likely stopping positions on any spin. The presence of that extra pocket does not change how the game is played round to round, but it changes what each bet is worth in the long run, because the payout odds stay the same while the number of losing positions increases.
What you are betting on
Every roulette wager is a bet on where the ball will land. The wheel spins in one direction, the ball travels in the other, and the outcome is whichever numbered pocket holds the ball when the wheel stops. The layout on the table lets you bet on a single number, groups of numbers, colours, odd or even, and high or low ranges. Each bet pays at fixed odds, and those odds do not shift between the 37-slot and 38-slot wheels.
What shifts is the probability behind the payout. A straight-up bet on one number pays 35 to 1 on both wheels. On a 38-slot wheel, there are 38 possible outcomes and one winning pocket, so the payout does not match the true odds of 37 to 1 against. That gap between the payout and the true odds is the house edge, and the double zero widens it on every bet type.
How a round moves from buy-in to settlement
You buy in at the table by placing cash on the layout, and the dealer exchanges it for roulette chips. These chips are usually a distinctive colour so the dealer can tell your bets from those of the other players. You do not have to use them outside the table; they are converted back to cash chips when you leave.
Once the dealer announces that betting is open, you place chips on the layout. You can cover as many positions as you like. When the dealer calls no more bets, the wheel is already spinning or about to be. The ball drops, the wheel slows, and the ball settles into a pocket. The dealer marks the winning number, clears the losing bets, and pays the winners at the printed odds. Your chips stay on the layout until the next round unless you pick them up.
Where the double zero shows up in the edge
House edge and RTP are complements: for the same bet under the same rule set, they sum to 100%. A 38-slot wheel has a built-in edge on every bet because there are 38 outcomes but the payouts are calculated as if there were 36. The table below compares the main bet types on the 38-slot layout and shows how the double zero changes what each wager returns over a very large number of spins.
| Bet type | Covers | Payout | What the double zero does |
|---|---|---|---|
| Straight-up | One number | 35 to 1 | Adds a second losing number, so the payout sits further below true odds |
| Split | Two adjacent numbers | 17 to 1 | Same edge as a straight-up bet; the extra pocket applies to both losing positions |
| Street | Three numbers in a row | 11 to 1 | Payout is fixed, but the wheel now has 38 stops instead of 37 |
| Corner | Four numbers | 8 to 1 | The double zero widens the gap between true odds and payout |
| Red or black | 18 numbers | 1 to 1 | Both zero pockets lose, so the player wins on 18 of 38 outcomes |
| Odd or even | 18 numbers | 1 to 1 | Same as red or black; the zeros are neither odd nor even for this bet |
| High or low | 18 numbers | 1 to 1 | Zeros fall outside both ranges and count as losing positions |
No bet on the 38-slot wheel escapes the extra pocket. Some players assume the even-money bets are safer because they cover nearly half the wheel, but the double zero means those bets win on 18 of 38 spins, not 18 of 36. The payout stays at 1 to 1, so the shortfall is the same structural gap that appears on every other bet.
Betting systems do not remove the extra pocket
A common move at the roulette table is to change the size of the next bet based on the previous result. Doubling after a loss, covering both red and black, or alternating between columns are all ways of rearranging how much money is at risk on each spin. None of them changes the fact that the wheel has 38 pockets and the payouts are fixed.
What a betting pattern changes is the shape of the session, not the edge. A progression can produce many small wins followed by one large loss, or a long flat stretch punctuated by a single winning spin. The house edge remains on every wager, because it is a property of the wheel and the payout schedule, not of the order in which you place chips.
What is under your control at the table
You cannot alter the wheel, but you can choose which bets you make and how long you play. The even-money bets on a 38-slot wheel carry the smallest edge among the standard wagers, while the five-number bet covering 0, 00, 1, 2 and 3 carries a larger one because it pays 6 to 1 on a five-number group. The specific edge for each bet is printed in the game information panel or the table rules where you play, and it is worth reading before you put chips down.
Session length matters because the edge expresses itself over many spins. A short session can end anywhere; a long one gives the arithmetic more room to work. Setting a stop-loss before you sit down, and treating the buy-in as the cost of the session, keeps the decision about when to leave from being made in the heat of a losing streak.
Procedural mistakes new players make
The first is betting after the dealer has called no more bets. Roulette tables run on a strict sequence, and a late hand across the layout can interfere with the ball or with another player's chips. Watch the dealer, and place your bets only while betting is open.
The second is picking up chips from a winning bet before the dealer has finished paying the table. The dealer settles bets in a fixed order, and moving your chips early can confuse the payout. Leave everything in place until the dealer pushes your winnings to you.
The third is confusing the two zero pockets when placing a bet that covers one of them. A split between 0 and 00 is a valid bet on the 38-slot layout, but it is easy to misplace the chip so it covers only one number. If you want both zeros, say so or place the chip on the line between them.
FAQ
Why does a roulette wheel have 38 slots instead of 37?
The 38-slot layout adds a double zero to the single-zero wheel. The second zero pocket gives the house an additional winning position on every spin, which widens the gap between the payout odds and the true odds on all bets.
Is the house edge the same on every bet on a 38-slot wheel?
Most standard bets share the same edge, but the five-number bet covering 0, 00, 1, 2 and 3 carries a larger one because its payout is set at 6 to 1 for a five-number group. The exact edge for each bet is stated in the game information panel where you play.
Can I bet on both zero and double zero at the same time?
Yes. A split bet placed on the line between 0 and 00 covers both pockets and pays 17 to 1. It is a two-number wager like any other split, and the double zero is simply one of the two losing positions when the ball lands elsewhere.
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This article is general information about how these mechanics work. It is not legal advice and not a recommendation to gamble or to use any particular operator. Availability and legality differ by jurisdiction — check the rules that apply where you are.