The wheel you sit down at changes the answer
Walk up to a roulette table and the first thing worth checking is not your chip stack but the wheel itself. Two main layouts circulate in casinos, and they do not carry the same number of red and black pockets. On the layout most common outside the United States, the wheel holds 37 pockets: 18 red, 18 black, and one green zero. On the layout still widely found in American venues, the wheel holds 38 pockets: the same 18 red and 18 black, plus two green pockets, a zero and a double zero.
So the direct answer is that both main wheel types contain 18 red numbers and 18 black numbers. What changes is the number of green pockets, and that single difference is enough to alter the house edge on every bet you can place.
Where the colours sit
Roulette does not alternate red and black in a strict pattern all the way around the wheel. The sequence is deliberately arranged so that high and low numbers, odd and even numbers, and red and black pockets are scattered. The zero and double zero are always green, which is why they belong to no outside bet category: they are neither red nor black, neither odd nor even, and neither high nor low.
Because the colours are fixed by the wheel's design, the count never varies within a wheel type. A European-style wheel always has its 18 red and 18 black pockets arranged in the same sequence. An American-style wheel always adds the second green pocket. What the player controls is which table they choose, and that choice has a measurable cost.
| Wheel type | Total pockets | Red numbers | Black numbers | Green pockets | Effect on the player |
|---|---|---|---|---|---|
| European-style, single zero | 37 | 18 | 18 | 1 | Fewer green pockets, lower house edge than the American layout |
| American-style, double zero | 38 | 18 | 18 | 2 | Extra green pocket raises the house edge on the same bets |
Why the green pocket changes the cost of every bet
Roulette pays winning bets as if the green pockets did not exist. A straight-up wager on a single number pays 35 to 1, even though the wheel has 37 or 38 pockets. A red-or-black bet pays even money, even though the green pocket means red and black together do not cover the whole wheel. That gap between the payout and the true odds is the house edge, and it is built into the geometry of the wheel rather than into any decision you make after the ball is spinning.
On a European-style wheel, a bet on red wins on 18 pockets and loses on 19: the 18 black numbers plus the single green zero. On an American-style wheel, the same bet wins on 18 pockets and loses on 20. The added double zero is an extra losing pocket for every outside bet, which is why the American layout carries the higher house edge. The colour count is identical; the green count is not.
What a round looks like
Knowing the wheel layout is the starting point. The sequence of play matters too, because several procedural mistakes happen before the ball is even released. When you sit down, you exchange cash for roulette chips at the table. These chips are usually a distinct colour per player so the dealer can tell stacks apart, and they have no cash value away from that table. You cash them back at the same table before you leave.
Once the dealer opens betting, you place chips on the layout. You may bet a single number, a group of numbers, red or black, odd or even, high or low, or a combination. The dealer spins the wheel, releases the ball in the opposite direction, and at some point announces that no more bets may be placed. From that call until the ball settles, your chips are fixed. After the ball lands, the dealer marks the winning number, clears losing bets, and pays winners according to the posted payout for that bet type.
Bet types and the edges they carry
Roulette looks like one game with many ways to bet, but the bets do not all cost the same. Some bets return more when they win and hit less often; others hit often and pay little. The table below compares the main bet families on a single-zero wheel. The same relationships hold on a double-zero wheel, with every house edge higher because of the extra green pocket.
| Bet type | What it covers | Payout | How often it tends to hit | Relative house edge |
|---|---|---|---|---|
| Straight-up | One number | 35 to 1 | Rarely | Higher |
| Split | Two adjacent numbers | 17 to 1 | Rarely | Higher |
| Street | Three numbers in a row | 11 to 1 | Occasionally | Higher |
| Corner | Four numbers meeting at a corner | 8 to 1 | Occasionally | Higher |
| Six line | Six numbers in two rows | 5 to 1 | Sometimes | Higher |
| Red or black, odd or even, high or low | 18 numbers | Even money | Often | Lower |
The even-money bets carry the lowest house edge on the table, but that does not make them a path to profit. It means the expected rate of loss per unit wagered is smaller than on the inside bets. The edge remains negative on every bet, every spin, regardless of what has just happened.
Mistakes that cost new players before the spin
The first procedural mistake is treating roulette chips like cash. Because every player at a table may hold a different colour, a red chip from one roulette table has no value at the cashier or at another table. Leaving the table without exchanging them back turns them into souvenirs.
The second is placing a late bet. Once the dealer calls no more bets, any chip that lands on the layout is void or returned, and repeated late betting will draw a warning. The call is not a suggestion; it is the point at which the round is closed.
The third is misreading the wheel type. A player who assumes every roulette wheel is the same may sit at a double-zero table without realising they are paying a higher built-in cost on every wager. The wheel is visible before you buy in, and the green pockets are the fastest way to tell which layout you are facing.
Why the colours matter more than the pattern
Players sometimes ask whether red or black is more likely on the next spin because of what has already appeared. The wheel has no memory, and the physical layout does not make one colour more probable than the other. On a single-zero wheel, red and black each occupy 18 of 37 pockets, so neither colour is more likely; the green zero is the pocket that tips every outside bet against the player. On a double-zero wheel, red and black remain equally likely, and the two green pockets tip the same bets further.
The colour count is a fixed fact of the equipment. What changes between tables is the number of green pockets, and that is the number worth reading before you put a chip down.
FAQ
Do all roulette wheels have the same number of red numbers?
Yes. Both the main wheel types contain 18 red numbers. The difference between them is in the green pockets: one green zero on a European-style wheel, two green pockets on an American-style wheel.
Is red or black more likely to come up next?
Neither. Red and black each occupy the same number of pockets on both main wheel types, so the two colours are equally likely on any spin. The green pocket or pockets are what make every red-or-black bet a losing proposition over the long run.
How can I tell which wheel I am playing before I bet?
Look at the wheel itself. A single green zero means a 37-pocket layout. A green zero and a green double zero together mean a 38-pocket layout with a higher house edge on every bet. The table layout usually prints the same information near the betting area.
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