The wheel you sit down at changes every number that follows
Before you buy a single chip, look at the wheel. If it has one green zero, there are 37 possible results on every spin. If it has a zero and a double zero, there are 38. That one extra pocket is not a cosmetic difference; it changes the payout odds on every bet you can place, and it changes how fast your money drains over a long session. A player who learns roulette on a single-zero wheel and then sits at a double-zero table without noticing has already given the house a larger share of every wager before the ball is even released.
The numbered pockets run from 0 to 36. On a single-zero wheel, that is 37 results in total: the numbers 1 through 36 plus the single zero. On a double-zero wheel, the same 1 through 36 sequence appears, plus a zero and a double zero, making 38. The zeros are usually green, and they are not odd or even, not high or low, and not red or black. They exist outside the even-money bets, which is precisely why they matter.
What counts as a result
A result in roulette is the single pocket in which the ball comes to rest. Nothing else is a result. The ball does not land on red; it lands on 14 red. It does not land on odd; it lands on 33 black. Every spin produces exactly one numbered pocket, and every bet you place is a wager that the result will fall inside some set of pockets you have chosen.
This matters because many players think of roulette as a game of red versus black or odd versus even. It is not. Those are just two of many ways to group the 37 or 38 pockets. The underlying event is always the same: one pocket, chosen by the wheel, from a fixed set that never changes size during a session.
The two wheel types and what changes between them
Roulette wheels come in two standard layouts, and the difference is entirely about the zeros. The comparison below shows what stays the same and what moves.
| Feature | Single-zero wheel | Double-zero wheel |
|---|---|---|
| Total pockets | 37 | 38 |
| Numbered pockets | 0 through 36 | 0 through 36 plus 00 |
| Zero pockets | One | Two |
| House edge on a straight-up bet | Lower | Higher |
| Payout for a winning straight-up bet | Same | Same |
The payout for a winning single-number bet is the same on both wheels, but the chance of winning it is not. On a single-zero wheel, a straight-up bet covers one pocket out of 37. On a double-zero wheel, it covers one pocket out of 38. The payout has not improved to compensate for the extra pocket, so the house keeps a larger mathematical share on the double-zero layout. The same logic applies to every bet on the table: the set of winning pockets is the same size, but the total pool of possible results has grown by one.
How the bet types divide the possible results
Every roulette bet is a claim about which subset of the 37 or 38 pockets will contain the result. The table below shows the main bet types, how many pockets each covers on a single-zero wheel, and what that means for the payout. The double-zero wheel adds one losing pocket to every row without changing any payout.
| Bet type | Pockets covered (single-zero wheel) | Payout | What you are claiming |
|---|---|---|---|
| Straight-up | 1 | Highest fixed payout | The ball lands on one exact number |
| Split | 2 | Lower than straight-up | The ball lands on either of two adjacent numbers |
| Street | 3 | Lower than split | The ball lands on one of three numbers in a row |
| Corner | 4 | Lower than street | The ball lands on one of four numbers that meet at a corner |
| Six line | 6 | Lower than corner | The ball lands on one of six numbers in two adjacent rows |
| Dozen or column | 12 | Lower than six line | The ball lands in a block of twelve numbers |
| Red, black, odd, even, high, low | 18 | Even money | The ball lands in one of eighteen pockets sharing a property |
Notice the pattern: the more pockets a bet covers, the lower the payout, because the bet wins more often. But no bet covers all 37 pockets, and the uncovered pockets are where the house edge lives. On an even-money bet like red, you cover 18 pockets but 19 remain uncovered on a single-zero wheel: the 18 black numbers plus the zero. On a double-zero wheel, 20 pockets remain uncovered. That gap between the pockets you cover and the pockets you do not is the entire economics of the game.
The sequence of a round, from buy-in to settlement
Roulette moves fast, and the procedure is the same on every wheel. Knowing the sequence before you sit down prevents the most common procedural mistakes.
First, you buy chips at the table. Roulette chips are typically a distinct colour per player so the dealer can tell stacks apart. You state a buy-in amount, and the dealer hands you a stack of colour chips with a value printed or announced. These chips are only valid at that table; you cannot carry them to another table or the cashier. When you finish, the dealer converts your colour chips back into standard cash-value chips.
Second, the dealer opens betting. You place chips on the layout, either on a single number or on the lines and intersections that represent groups of numbers. You can place multiple bets on the same spin, and many players do. The dealer will announce when no more bets are accepted, usually as the ball begins to slow.
Third, the ball lands. The dealer marks the winning number on the layout, removes losing bets first, and then pays winning bets. The payout for an even-money bet is one unit for every unit wagered. A straight-up bet pays a fixed multiple printed on the table layout; the exact multiple is the same on both wheel types, but the chance of collecting it is not.
Fourth, the dealer clears the layout and the next round begins. You may leave bets in place, move them, add to them, or sit out a spin. Nothing requires you to bet every round.
What the house edge means for one session
The house edge is the share of each wager the operator expects to keep over a very large number of spins. It is not a fee collected per spin, and it does not predict what happens in the next hour. On any single spin, you either win or lose the whole bet. Over thousands of spins, the gap between the pockets you cover and the pockets you do not shows up as a steady expected loss.
Roulette has no decision that changes the edge after the bet is placed. Unlike blackjack, where the player chooses whether to hit or stand, a roulette bet is a one-time claim about where the ball will land. The only choices that affect the expected rate of loss are the wheel you sit at, the bet types you choose, and how many spins you play. A straight-up bet has a larger house edge than an even-money bet on the same wheel because the payout does not fully compensate for the lower chance of winning. Different bets on the same table carry materially different edges, and a player who moves from an even-money bet to a straight-up bet has changed the expected rate of loss, not the chance of a big win in any predictable way.
Procedural mistakes that cost new players
The first mistake is sitting at a double-zero wheel without noticing. The second is treating colour chips as cash and walking away from the table with them. The third is placing a bet after the dealer has called no more bets, which will simply be returned or refused, and which slows the table for everyone. None of these is a strategy error; they are all procedural, and all of them are avoidable by watching one full round before you buy in.
A fourth mistake is assuming that because red has appeared five times in a row, black is more likely next. The wheel has no memory. Every spin draws from the same 37 or 38 pockets, and the previous results do not remove pockets from the wheel. A run of reds changes nothing about the next spin except how it feels.
Finally, some players believe a betting progression can overcome the uncovered pockets. It cannot. Doubling a bet after a loss changes the size of the amounts at risk, not the chance of winning the next spin. The edge remains on every wager, and a progression redistributes wins and losses across a session rather than removing the built-in disadvantage.
FAQ
Why does the double zero change the odds on every bet?
The double zero adds one more pocket to the wheel without improving any payout. A bet that covered 18 pockets out of 37 now covers 18 out of 38, so it wins slightly less often while paying the same amount. The same logic applies to every bet type, because the total pool of results has grown but the winning subsets have not.
Can a roulette spin land on the same number twice in a row?
Yes. Each spin is independent, and the wheel does not remember previous results. A number that just hit has the same chance of hitting again on the next spin as any other number on the wheel. Streaks and repeats are normal parts of random sequences, not signs that the wheel is broken or due to change.
Do all roulette tables use the same number of pockets?
No. The two standard layouts are the single-zero wheel with 37 pockets and the double-zero wheel with 38. The wheel type is printed on the layout or visible on the wheel itself, and it is the first thing to check before buying in, because it changes the house edge on every bet you can place.
Gamble responsibly. If you or someone you know has a gambling problem, call the helpline printed in the footer below.
Play responsibly
Gambling should be treated as paid entertainment, never as a way to earn income or recover losses. 1-800-MY-RESET (1-800-697-3738)
18+ or 21+ depending on where you are; follow the minimum age that applies to you.
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.