The moment the ball lands in the green pocket
You have chips on even, the wheel slows, and the ball settles into the pocket marked 0. The dealer sweeps your bet away. If you expected an even-money payout because zero is a round number, the layout has just taught you otherwise. In roulette, 0 is not even, not odd, not red, and not black. It is a category of its own, and that category is the quiet engine behind the game's mathematics.
Understanding what zero is on the wheel matters more than the label. It decides which outside bets lose when it appears, how the house edge is built, and why two wheels that look nearly identical can cost a player at different rates over a long session.
How the layout classifies numbers
A roulette table divides every number into overlapping groups. The inside bets sit on the numbered grid. The outside bets surround it: red or black, odd or even, and low (1-18) or high (19-36). Each outside bet is designed as a near-even split of the pockets that pay an even-money return.
The split is near-even, not exact, because of zero. On a European wheel, 18 pockets are red, 18 are black, and one is green. The same arithmetic applies to odd and even: 18 odd numbers, 18 even numbers, and one pocket that belongs to neither side. When the ball lands in that green pocket, every even-money outside bet loses on most standard layouts. The zero is not counted as a loss because it is even; it is counted as a loss because the bet's winning condition is defined as the ball landing on one of the 18 pockets that carry the even label.
Some tables soften this with a rule called la partage or en prison, where an even-money bet that loses to zero returns half the stake or holds it in place for the next spin. Whether that rule exists is printed in the table's own rules, and it changes the cost of zero materially. The classification of zero itself, however, does not change: it remains outside the odd/even and red/black splits.
What zero does to the house edge
House edge and RTP are complements: they sum to 100% for the same bet under the same rule set. An even-money bet on a European wheel pays 1:1, but the player is not choosing between 36 outcomes. There are 37 pockets, and one of them, the zero, belongs to the house on that bet. The bet wins on 18 pockets and loses on 19. That one-pocket imbalance is the entire house edge on the even-money wagers.
An American wheel adds a second green pocket, the double zero. The wheel now has 38 pockets, while the even-money bets still win on only 18 of them. The extra pocket increases the house edge on the American layout compared with the European layout, because the player's winning condition has not changed while the number of losing pockets has grown by one.
The comparison that matters to a player choosing a table is not the colour of the felt but the number of green pockets on the wheel:
| Wheel type | Pockets | Green pockets | Effect on even-money bets |
|---|---|---|---|
| European | 37 | 1 (single zero) | 18 winning pockets, 19 losing pockets |
| American | 38 | 2 (single and double zero) | 18 winning pockets, 20 losing pockets |
The zero does not change how much an even-money bet pays. It changes how often the bet wins. Over a very large number of spins, that difference in frequency is the house edge expressed in money.
Inside bets and the zero
Zero also appears on the inside of the layout, where it behaves like any other number for the purpose of straight-up and combination bets. A chip placed directly on the 0 wins if the ball lands there, and it pays at the standard straight-up rate for that table. A split bet between 0 and 1, or between 0 and 2, covers both pockets and pays at the split rate. On an American wheel, the 00 is a separate pocket with its own straight-up and split options, and some layouts offer a five-number bet covering 0, 00, 1, 2 and 3.
The inside bets are not affected by zero's exclusion from red, black, odd or even. A straight-up bet on zero wins when zero appears, full stop. The exclusion matters only for the outside bets whose winning condition is defined by a category that zero does not belong to.
Reading the table before you buy in
Roulette is a game where the sequence of a round is simple, but the cost of a mistake is immediate. A player buys in at the table, receives chips in a colour specific to that seat, and places bets before the dealer calls no more bets. The wheel spins, the ball settles, the dealer marks the winning number, and losing bets are cleared before winning bets are paid. The whole round moves fast enough that a misunderstood outside bet can be repeated several times before the player notices.
Before the first spin, confirm three things on the layout itself. First, count the green pockets: a single zero or a single and double zero. Second, check whether the table posts a la partage or en prison rule, because that changes what happens to an even-money bet when zero appears. Third, look at the minimum and maximum posted for outside bets, which are often separate from the inside limits.
The procedural mistakes new players make at roulette are usually about timing and placement, not strategy. Placing a bet after the dealer has called no more bets is the most common, and the bet will be returned or refused. Stacking chips in a way that straddles two betting areas creates ambiguity about which bet was intended, and the dealer will resolve it according to the position of the stack, not the player's intention. Touching chips after the result is announced is treated as an attempt to alter a settled bet. Each of these is resolved by the dealer at the table, but they are all avoidable by placing one bet at a time and keeping hands away from the layout once the ball is in motion.
What a strategy chart can and cannot do for roulette
Roulette is not a game where published strategy charts change the underlying mathematics the way a blackjack basic-strategy chart does. In blackjack, a chart derives from a specific rule set: the number of decks, whether the dealer stands on soft 17, and the doubling and splitting rules all change the correct play. Roulette has no equivalent decision tree. The player chooses which bets to place, and every bet on the table carries its own house edge under the same wheel.
What a player can control is which bets they place and for how long. A straight-up bet on a single number pays more but wins less often. An even-money bet wins more often but pays less. Neither changes the house edge built into the wheel. The zero pocket is always present, and on most layouts it always takes the even-money bets. A betting pattern, however carefully arranged across the layout, does not remove that pocket.
The honest way to approach roulette is to treat it as a game of fixed odds where the wheel's structure, not the player's system, sets the long-run cost. Choosing a single-zero wheel over a double-zero wheel is a real choice that changes the expected rate of loss. Choosing red over black is not.
FAQ
Does 0 count as odd in roulette?
No. Zero is outside both the odd and even categories. On a standard layout, an odd bet and an even bet both lose when the ball lands in the zero pocket, unless the table applies a rule such as la partage or en prison that returns or holds part of the stake.
What happens to a red or black bet when 0 hits?
The same thing that happens to an odd or even bet: it loses on most layouts, because zero is green and belongs to neither colour. A table with a la partage or en prison rule may return half the bet or hold it for the next spin, but that rule must be posted on the table itself.
Is a bet on 0 itself a good bet?
A straight-up bet on zero pays at the table's standard straight-up rate and wins when the ball lands in that pocket. It does not carry a different house edge from other straight-up bets on the same wheel. The bet is neither better nor worse than betting on any other single number; it simply covers one pocket out of the wheel's total.
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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.