The Question Hides a Wheel, Not a Die
When someone asks how many sides a roulette wheel has, they are usually picturing a spinning disc and trying to count its segments the way they would count faces on a die. A roulette wheel does not have sides in that sense. It has pockets: recessed compartments around the rim where the ball comes to rest. The number of pockets is the figure that matters, because it sets the arithmetic for every bet on the table.
There are two common layouts. A European wheel carries 37 pockets, numbered 0 through 36, with a single zero. An American wheel carries 38 pockets, numbered 0 through 36 plus a second zero pocket marked 00. The extra pocket on the American layout is not a cosmetic difference. It changes the probability of nearly every wager, and it is the reason two wheels that look similar can hold different edges for the player.
Some venues also offer variants with different pocket counts or special rules, but the 37-pocket and 38-pocket wheels are the ones you will meet almost everywhere. When you sit down, the wheel itself tells you which one you are playing: look for a 00 pocket before you place a chip.
What the Pockets Are
Each pocket is a numbered slot, coloured red or black, with the zero pockets in green. The numbers are not arranged in numerical order around the wheel. They are distributed in a sequence designed to alternate colours and spread high and low numbers around the rim. The layout printed on the felt, where you place bets, follows numerical order. The wheel itself does not.
That distinction matters because some bets are about the wheel's physical arrangement, not the felt. A neighbour bet, offered at some tables, covers a number and the pockets that sit next to it on the wheel. The sequence of pockets around the rim therefore affects which numbers that bet includes. The pocket count, by contrast, affects every bet on the table.
The ball is spun in the opposite direction to the wheel and eventually drops into one pocket. The outcome is a single pocket. Every wager is settled against that one result, and the probability of any given pocket is one divided by the total number of pockets, assuming a fair wheel and a random spin.
Why the Extra Pocket Changes the Arithmetic
A straight-up bet on a single number pays 35 to 1 on both wheel types. On a 37-pocket wheel, the true odds against hitting that number are 36 to 1, because there are 36 losing pockets and one winning pocket. On a 38-pocket wheel, the true odds are 37 to 1. The payout stays the same, but the chance of winning shrinks. That gap between the payout and the true odds is the house edge.
The same principle applies to outside bets. A bet on red covers 18 pockets. On the European wheel, 18 of 37 pockets win, so the chance is just under half. On the American wheel, 18 of 38 pockets win, so the chance is slightly lower again. The zero pockets are not covered by red, black, odd, even, high or low bets, which is how the house keeps its advantage on those wagers.
RTP and house edge sum to 100% for the same bet under the same rule set. If a given roulette bet carries a house edge of one figure on a European wheel, the same bet carries a higher edge on an American wheel because the denominator has changed. The game's structure is identical; only the number of losing pockets differs.
Comparing the Two Main Wheels
The table below sets out the structural differences that follow from the pocket count. These are mechanical facts about the wheels, not statements about any particular venue or operator.
| Feature | European wheel | American wheel |
|---|---|---|
| Pockets | 37 | 38 |
| Zero pockets | One (0) | Two (0 and 00) |
| Number range | 0-36 | 0-36 plus 00 |
| Payout for a straight-up bet | 35 to 1 | 35 to 1 |
| True odds against a straight-up win | 36 to 1 | 37 to 1 |
| Effect on house edge | Lower on equivalent bets | Higher on equivalent bets |
The payout column is identical because the game's pay table does not change with the wheel. What changes is the probability underneath it. That is the entire difference between the two layouts, and it is why a player who understands the pocket count reads the wheel before reading the felt.
How a Round Moves from Buy-In to Settlement
You begin by buying in at the table, exchanging cash for roulette chips. Roulette chips are often colour-coded to a single player at a live table, which is why they cannot be used at other tables and must be cashed in before you leave. The dealer, or croupier, handles the wheel and the ball; players place chips on the layout themselves.
Betting opens, and players place wagers on the felt. Inside bets sit on individual numbers or small groups of numbers. Outside bets sit in the boxes around the numbered grid and cover larger categories such as red or black, odd or even, or a dozen numbers. You may place multiple bets on the same spin, and each bet is settled independently against the same result.
The croupier then spins the wheel and launches the ball in the opposite direction. At some point the croupier announces that no more bets may be placed. Once the ball drops into a pocket, the croupier marks the winning number, clears losing bets, and pays winners. The sequence repeats. Your chips remain in play until you decide to stop and cash out at the table.
Inside Bets, Outside Bets, and the Edges They Carry
Roulette carries a wider spread of bet types than most table games, and the house edge is not uniform across all of them. Some bets pay more but win less often; others pay close to even money but cover nearly half the wheel. The table below summarises the main categories and how they differ in coverage and payout structure.
| Bet type | What it covers | Payout | How it behaves |
|---|---|---|---|
| Straight-up | One number | 35 to 1 | Rare wins, large payout |
| Split | Two adjacent numbers | 17 to 1 | Slightly more frequent wins |
| Street | Three numbers in a row | 11 to 1 | Moderate coverage |
| Corner | Four numbers meeting at a corner | 8 to 1 | Broader coverage, lower payout |
| Six line | Six numbers in two rows | 5 to 1 | Wider inside coverage |
| Red or black | 18 pockets of one colour | 1 to 1 | Frequent wins, small payout |
| Odd or even | 18 pockets | 1 to 1 | Same structure as colour |
| High or low | 18 pockets | 1 to 1 | Same structure as colour |
The table shows coverage and payout, not edge. The edge on any given bet follows from the wheel type, because the zero pockets are excluded from the even-money categories and the payouts do not match true odds on the inside bets. On a single-zero wheel, the house edge on most bets is lower than on a double-zero wheel, but the relationship between bet types stays the same: no bet on the layout removes the house advantage.
Some tables also offer announced bets, which cover sections of the wheel rather than sections of the felt. These are more common on European layouts and are settled against the same single outcome. Their edges follow the same arithmetic as the bets they contain.
What a Strategy Chart Does and Does Not Do
Roulette does not have a decision chart in the way blackjack does, because the player makes no choices after the ball is released. The only decisions are which bets to place, how much to stake, and when to stop. Published strategy material for roulette therefore concentrates on bet selection and bankroll management, not on changing the outcome of a spin.
Where a chart does exist, it derives from the exact rule set in use. A single-zero wheel produces different expected-loss figures than a double-zero wheel, and a table with a special rule, such as one that returns half an even-money stake when the ball lands in zero, changes the arithmetic again. A chart built for one rule set does not transfer cleanly to another. Read the wheel first, then read the chart.
The same principle applies to any published house-edge figure. It is a long-run statistical average over a very large number of spins, not a prediction for your session. A short session can end above or below the average, and the average itself is set by the wheel's structure, not by the player's choices.
Procedural Mistakes That Cost New Players
The first mistake is placing a bet after the croupier has called no more bets. Late bets are void or returned, and at a busy table the window closes quickly. Watch the croupier's hand and the ball, not just the felt, and have your chips placed before the call.
The second mistake is treating roulette chips like cash chips. At many live tables, roulette chips carry no denomination printed on them and are valid only at that table. Walking away with them means carrying value that cannot be used elsewhere. Cash out at the table before you leave.
The third mistake is assuming the wheel type from the venue's reputation or the table's appearance. The only reliable check is the wheel itself. Look for the 00 pocket. If it is present, you are on a 38-pocket wheel, and every bet you place carries the arithmetic that goes with it.
FAQ
Why does the American wheel have an extra pocket?
The double-zero pocket is a design variant that increases the number of losing pockets for most bets. It changes the house edge on the American layout compared with the single-zero European layout, without changing the payouts.
Do all roulette wheels have the same numbers?
The standard wheels carry 0 through 36, with the American layout adding 00. Some novelty or electronic variants may use a different sequence or a reduced set of pockets, but the two standard layouts dominate live tables.
Does the number of pockets affect how often I win?
Yes. The chance of any single pocket is one divided by the total number of pockets, so a 38-pocket wheel gives each number a slightly lower probability than a 37-pocket wheel. The payouts stay the same, which is why the extra pocket increases the house edge.
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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.