The pocket that decides almost every roulette bet
A roulette wheel looks simple from across the table: red numbers, black numbers, and one or two green spaces that seem to belong to neither side. Those green spaces are the zero pockets, and they are the reason the casino holds an edge on nearly every wager you can place. When the ball lands in a green pocket, the red-versus-black, odd-versus-even, and high-versus-low bets all lose. The green space is not a neutral outcome; it is the house's number.
The colour coding is deliberate. Red and black alternate around the wheel, but the zeros sit apart in green so that players can see at a glance that they are special. On a European wheel, there is a single green pocket marked 0. On an American wheel, there are two: 0 and 00. Both are green, and both function the same way for the outside bets that most new players make first.
What the zero does to a bet
To see why the green pocket matters, consider the simplest wager on the layout: red or black. A European wheel has 37 pockets in total — the numbers 1 through 36, plus the single zero. Eighteen of those numbered pockets are red and eighteen are black. If the wheel had no zero, a red bet would win on 18 of 36 spins and lose on the other 18, and the bet would pay even money with no built-in advantage to either side.
The zero changes that arithmetic. A red bet on a European wheel still wins on 18 pockets, but now loses on 19 — the 18 black numbers plus the green zero. The payout remains even money, so the player is paid as if the odds were still 18 against 18 when they are 18 against 19. That one-pocket gap is the house edge on the bet. On an American wheel, the double zero widens the gap to 20 losing pockets against 18 winning ones, which is why the same red or black bet carries a larger edge on that layout.
The same logic applies to odd or even and to the high and low halves of the layout. The zeros are not odd, not even, not high, and not low. They sit outside every outside bet, and that is exactly where the operator's advantage lives.
European and American wheels compared
The number of green pockets is the fastest way to tell the two common wheel types apart, and it changes the mathematics of every bet on the table.
| Feature | European wheel | American wheel |
|---|---|---|
| Total pockets | 37 | 38 |
| Green pockets | One (0) | Two (0 and 00) |
| Red and black pockets | 18 of each | 18 of each |
| Effect on outside bets | 19 losing pockets against 18 winning | 20 losing pockets against 18 winning |
| House edge on the same bet | Lower | Higher |
The extra green pocket on the American layout does not change the payout on any bet. A winning red bet still pays even money on both wheels. What changes is how often the bet wins, and that is enough to make the American wheel the more expensive game for the player. The difference is not a matter of style or tradition; it is built into the wheel itself.
How a round plays
Walking up to a roulette table for the first time is easier when you know the sequence. The croupier opens the betting window, and players place chips on the layout. You may bet on individual numbers, on groups of numbers, or on the outside sections covering red, black, odd, even, high, or low. Once the croupier calls an end to betting, no further chips may be placed or moved.
The ball is spun in the opposite direction to the wheel's rotation. When it drops into a pocket, the croupier marks the winning number on the layout, removes the losing chips, and pays the winners. Only then may players touch their winnings or place new bets. The entire round, from the opening of betting to the clearing of the layout, takes less than a minute at a busy table.
Two procedural mistakes trip up new players more than any others. The first is reaching for chips after the croupier has called an end to betting; the second is placing a bet after the ball has already begun to slow. Both are treated seriously because they can be read as attempts to act on information the house has not yet declared. Wait for the croupier to finish clearing and paying before you touch anything on the table.
Inside bets, outside bets, and the zero
Roulette bets fall into two broad families. Inside bets are placed on the numbered grid and cover individual numbers or small groups of them. Outside bets sit around the grid and cover large categories. The zero pockets interact with these two families differently.
| Bet type | What it covers | How the green pocket affects it | Relative house edge |
|---|---|---|---|
| Straight-up | A single number | Zero is one possible losing number among many | Higher per bet |
| Split or street | Two or three adjacent numbers | Zero sits outside the covered group unless specifically bet | Higher per bet |
| Red, black, odd, even, high, low | 18 numbers | Zero loses the bet outright | Lower per bet |
| Zero or double zero | The green pocket itself | Pays at the same odds as a straight number | Same as any single-number bet |
You can bet on the green pocket directly. A straight-up bet on 0, or on 00 where the wheel has one, pays at the same rate as a bet on any other single number. Some layouts also offer a basket bet on American wheels that covers 0, 00, 1, 2 and 3 together, though the edge on that particular wager is higher than on most other bets at the table because it pays as if it covered fewer numbers than it does.
What the green pocket does not do
The green pocket does not make the wheel unfair, and it does not mean the game is rigged. The wheel is a mechanical device, and the zero is simply a printed number like any other. What the zero does is change the payout odds relative to the true odds of winning. The operator does not need to hide anything; the advantage is printed on the wheel in green.
It also does not mean a player can never win. Short sessions produce all kinds of results, including long runs of red, black, or a single number repeating. The green pocket is a long-run structural feature, not a per-spin punishment. Over a very large number of spins, however, the gap between the payout and the true odds accumulates in the operator's favour, and the zero is where that gap lives.
One more point worth making plainly: no betting pattern changes the zero's effect. Covering red and black at the same time, doubling after a loss, or spreading chips across many numbers does not remove the green pocket from the wheel. Those approaches redistribute when wins and losses land; they do not alter the underlying arithmetic of the game.
FAQ
Why is the zero green on a roulette wheel?
The zero is coloured green to distinguish it from the red and black numbered pockets. Since the zero is not covered by red, black, odd, even, high, or low bets, the colour signals at a glance that it sits outside those categories and loses for all of them.
Does the green pocket pay out if the ball lands on it?
Only if you have placed a bet that covers it. A straight-up bet on the zero pays at the same odds as a bet on any other single number. If you have bet on red, black, odd, even, high, or low, the green pocket loses your wager.
Is one type of roulette wheel better for the player?
A wheel with a single zero gives the house a smaller edge on the same bet than a wheel with both a zero and a double zero. The payout is identical on both layouts; the difference is that the double-zero wheel has one more pocket that loses for the outside bets. Which wheel is available depends on the venue and the region.
If you or someone you know is struggling with gambling, help is available. Contact the National Problem Gambling Helpline at the helpline printed in the footer below for confidential support, or visit NCPGambling.org for resources and information. You must be 18+ or 21+ depending on your location to gamble. Please play responsibly.
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.