The Number That Changes the Whole Table
You walk up to a roulette table, buy in, and the first thing you should look at is not your chips or the betting layout. It is the wheel itself. Count the green pockets. If there is one green zero, you are looking at a European wheel with 37 spaces. If there are two green pockets, a zero and a double zero, the wheel has 38 spaces. That single extra pocket is the most important fact about the game, because it quietly increases the house edge on every bet you can make.
Roulette is a game of fixed odds and fixed payouts. The wheel does not care what you bet on, and neither does the ball. But the number of spaces on the wheel determines whether the payouts you receive are closer to or further from the true odds of your bet winning. Before you put a chip down, you should know which wheel you are on and what that means for your money.
The Wheel Layout, Pocket by Pocket
A roulette wheel is a shallow, spinning bowl with numbered pockets set around its rim. The numbers run from 0 to 36. On a European wheel, those 36 numbers plus the single zero make 37 spaces. On an American wheel, the 36 numbers plus the zero and the double zero make 38 spaces. The numbers are not arranged in numerical order around the wheel; they are distributed in a pattern designed to alternate red and black, high and low, odd and even as evenly as the wheel's geometry allows. The zero pockets are green, which is why they stand out immediately.
The betting layout on the table mirrors the wheel but is arranged differently. The inside area shows the individual numbers in a grid, with the zero or zeros at the top. The outside area holds the group bets: red or black, odd or even, high or low, dozens and columns. Every bet you can place is a wager on where the ball will land among those 37 or 38 spaces.
European Versus American: One Pocket, Two Different Games
The difference between the two wheel types is not cosmetic. It changes the mathematics of every bet on the table. Here is the comparison:
| Feature | European Wheel | American Wheel |
|---|---|---|
| Number of spaces | 37 | 38 |
| Green pockets | One (single zero) | Two (zero and double zero) |
| Number range | 0 to 36 | 0 to 36 |
| Effect on house edge | Lower edge on equivalent bets | Higher edge on equivalent bets |
| Common locations | More common in European and many online casinos | More common in North American land-based venues |
The extra double-zero pocket does not add a new way to win. It adds a new way to lose. When the ball lands in a green pocket, most outside bets and all straight-up number bets lose. On an American wheel, that happens more often, and the payouts do not increase to compensate. That is the entire story of why the wheel with more spaces is the worse deal for the player.
How the Number of Spaces Creates the House Edge
Roulette's house edge comes from a simple mismatch: the payout for a winning bet is calculated as if the wheel had 36 spaces, but the wheel has 37 or 38. A straight-up bet on a single number pays 35 to 1. If the wheel had 36 numbers and no zeros, that payout would exactly match the true odds of winning, and the game would be even. But the zero pockets sit on the wheel and pay nothing, while the payout stays at 35 to 1.
On a European wheel, a straight-up bet has one chance in 37 of winning but pays as if the chance were one in 36. That gap is the house edge. On an American wheel, the same bet has one chance in 38 but still pays 35 to 1, so the gap is wider. The same principle applies to every bet on the layout. The extra space on the American wheel does not change what you are paid; it only changes how often you are paid.
What Each Decision Point Means
A round of roulette moves quickly, but each step is a decision or an outcome you should understand before you sit down.
First, you buy in. You hand the dealer cash or a casino cheque, and you receive roulette chips. These are different from the chips used at other table games. Each player at a roulette table is assigned a chip colour so the dealer can tell whose bets are whose on the shared layout. These chips have no value printed on them; the dealer sets their value when you buy in, and they can only be cashed out at the roulette table, not at the main cashier.
Second, you place your bets. You can bet on a single number, a small group of numbers, or a large category like red or black. You may place multiple bets on the same spin. The dealer continues to accept bets until they announce that no more bets are allowed, usually as the ball begins to slow.
Third, the ball lands. The dealer marks the winning number on the layout and clears all losing bets first. Then winning bets are paid. Your losing chips are gone; your winning bets are paid at the fixed odds printed or implied by the layout. You leave your winning bet on the table if you want it to ride, or you collect it.
Finally, when you are done, you exchange your coloured roulette chips back for standard value chips at the table. You cannot take the coloured chips to another game or to the cashier.
The Main Bet Types and Their Different Edges
Not all roulette bets are equal. On a European wheel, the house edge is the same for most bets, but on an American wheel, one particular bet is worse than all the others. Here is how the main bet categories compare on a European wheel:
| Bet Type | What It Covers | Payout | House Edge on European Wheel |
|---|---|---|---|
| Straight up | One single number | 35 to 1 | Same base edge as all other bets |
| Split | Two adjacent numbers | 17 to 1 | Same base edge |
| Street | Three numbers in a row | 11 to 1 | Same base edge |
| Corner | Four numbers in a square | 8 to 1 | Same base edge |
| Red or black | 18 numbers of one colour | 1 to 1 | Same base edge |
| Odd or even | 18 numbers | 1 to 1 | Same base edge |
| High or low | 18 numbers (1-18 or 19-36) | 1 to 1 | Same base edge |
The key point is that on a European wheel, the house edge is uniform across all these bets because the payout structure is built around the same 37 spaces. On an American wheel, the edge is higher across the board. There is one exception worth knowing: some American wheels offer a five-number bet covering 0, 00, 1, 2 and 3. That bet pays 6 to 1, but because it covers five numbers on a 38-space wheel, its house edge is higher than every other bet on the table. If you see that bet available, it is the one to avoid.
What Strategy Charts Can and Cannot Tell You
Roulette is not a game where a strategy chart can change the underlying mathematics. In blackjack, a basic strategy chart derives from the specific rule set in use: how many decks, whether the dealer stands on soft 17, what doubling and splitting rules apply. Roulette has no decision points after the bet is placed. You choose which bets to make, and then the wheel decides.
What you can control is which wheel you play and which bets you avoid. If you have a choice between a European wheel with 37 spaces and an American wheel with 38, the European wheel is the better option for every bet you might place. If you are on an American wheel, you can still choose to avoid the five-number bet that carries the worst edge on the layout. Those are the only meaningful strategic choices roulette offers, and they are both about understanding the spaces on the wheel rather than predicting where the ball will land.
Procedural Mistakes New Players Make
The most common mistakes at a roulette table are not about picking the wrong number. They are about how you handle your chips and your bets.
The first mistake is trying to cash out coloured roulette chips at the main cashier. These chips are only valid at the roulette table where they were issued. You must exchange them with the dealer before you leave the table. Walking away with them means you have to come back to that exact table to convert them.
The second mistake is reaching onto the layout after the dealer has called no more bets. Once the ball is in motion and the dealer has closed betting, the layout is off limits. Touching your chips or trying to move a bet at that point will get you corrected immediately, and it looks like an attempt to alter a wager after the outcome is being decided.
The third mistake is placing a bet without knowing the table minimum. Roulette tables have minimums that apply to the total of your inside bets, your outside bets, or both, depending on the house rules. Ask before you buy in, or read the placard on the table. Buying in for a colour and then discovering your intended bets do not meet the minimum is an awkward way to start a session.
FAQ
Why does the American wheel have an extra space?
The double zero was added to American roulette wheels in the nineteenth century as a way to increase the house's advantage. It does not change the payouts; it simply adds one more losing pocket for most bets, which widens the gap between the true odds and the odds at which the house pays.
Does the number of spaces affect my odds on red or black?
Yes. On a European wheel, red or black covers 18 of 37 spaces. On an American wheel, it covers 18 of 38 spaces. The payout is the same even-money bet on both wheels, so the bet is mathematically worse on the wheel with more spaces because the green pockets count as losses for both red and black.
Can I tell which wheel a casino uses before I sit down?
Look at the wheel itself. A European wheel has one green zero pocket; an American wheel has a green zero and a green double zero. Online games usually state the wheel type in the game information panel or rules screen. The table layout will also show whether there is a double-zero space on the betting grid.
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