The wheel you are looking at has 18 red pockets
A European roulette wheel carries 37 numbered pockets. Of those, 18 are red, 18 are black, and one — the zero — is green. The word "spokes" in the question usually comes from a quick glance at the wheel, where the metal dividers between pockets can look like the spokes of a wheel. What the reader is really counting are the coloured pockets themselves, and the answer is the same whether you call them spokes, slots, or compartments: 18 red.
The numbers are not arranged in numerical order around the wheel. The sequence runs 0, 32, 15, 19, 4, 21, 2, 25, 17, 34, 6, 27, 13, 36, 11, 30, 8, 23, 10, 5, 24, 16, 33, 1, 20, 14, 31, 9, 22, 18, 29, 7, 28, 12, 35, 3, 26. The red and black pockets alternate as far as the arithmetic allows, and the single zero sits in its own green pocket at the top of the wheel.
This matters because the red-black split is the foundation of a large family of bets. A bet on red is a bet that the ball will land in any one of those 18 red pockets. A bet on black covers the other 18. The zero belongs to neither colour, which is why a red or black bet loses when the zero appears on a European wheel.
Why the zero changes the arithmetic of a colour bet
A colour bet pays even money: you stake one unit and receive one unit in profit if the ball lands on your colour. On a wheel with 37 pockets, there are 18 ways to win and 19 ways to lose, because the zero is a losing outcome for both red and black. That single green pocket is the entire reason the bet does not pay at true odds.
If the wheel had 36 pockets and no zero, an even-money bet on red would win 18 times and lose 18 times over a very large number of spins, and the bet would break even in the long run. The European wheel adds one pocket that favours nobody, and that pocket is where the operator's mathematical advantage on the colour bets comes from. The same logic applies to odd/even and high/low, the other even-money bets on the layout.
House edge and Return to Player are complements: they sum to 100% for the same bet under the same rule set. On a European wheel, the edge on a red or black bet is the proportion of the wheel represented by the zero relative to all 37 pockets. The RTP is the remainder. The exact figures are printed in the game information panel of the online table you are playing, and they are worth checking because a rule variant can shift them.
European and American wheels compared
Players sometimes assume every roulette wheel is the same. The difference between the two main layouts is structural, and it changes the expected rate of loss on every bet on the table.
| Feature | European wheel | American wheel |
|---|---|---|
| Total pockets | 37 | 38 |
| Zero pockets | One (single zero) | Two (single and double zero) |
| Red pockets | 18 | 18 |
| Black pockets | 18 | 18 |
| Green pockets | 1 | 2 |
| Effect on even-money bets | One losing pocket beyond the 18 winners | Two losing pockets beyond the 18 winners |
The American wheel keeps the same 18 red and 18 black pockets but adds a second green pocket, the double zero. That extra pocket increases the house edge on the American layout, because a colour bet now has 18 ways to win and 20 ways to lose. The red count itself does not change between the two wheels; what changes is the number of pockets that defeat the bet.
How a round of roulette runs
Roulette is the easiest table game to sit down at, but the sequence of a round is worth knowing before you put chips down. The wheel spins in one direction while the dealer sends the ball travelling the opposite way around the outer track. The ball loses speed, drops onto the wheel, bounces across the deflectors, and settles in one pocket. The outcome is determined by a random number generator in online play, with the animation representing the result; in a physical venue the ball and wheel do the work.
Betting opens before the spin and closes when the dealer announces it, or when the online table locks the betting window. Until that moment you can place, move, or remove chips on the layout. Once the window closes, the wager stands. After the ball settles, the dealer marks the winning number, clears losing bets, and pays winners according to the payout printed for that bet type.
Your buy-in is converted into roulette chips at the table. In a physical venue these are often colour-coded per player so the dealer can tell whose bet is whose. Online, your balance simply shows in the cashier and you select a chip value before placing it on the layout.
The bet types, and where the red count fits
Roulette bets fall into two broad groups. Inside bets sit on the numbered grid and cover specific numbers or small groups of them. Outside bets sit around the grid and cover larger categories: red or black, odd or even, high or low, and the dozens and columns. The red count is directly relevant to the red bet, but every outside bet is shaped by the same wheel arithmetic.
| Bet | What it covers | How the zero affects it |
|---|---|---|
| Red or black | 18 pockets of one colour | Zero loses; 18 winners against 19 losing pockets |
| Odd or even | 18 numbers of one parity | Zero loses; same 18-against-19 structure |
| High or low | 18 numbers in a range | Zero loses; same 18-against-19 structure |
| Single number | One pocket | Zero is just another losing pocket unless bet directly |
| Split (two numbers) | Two adjacent pockets | Zero can be included in a split with a neighbour |
Each bet type carries its own payout and its own edge. The even-money bets share the same structure because they all cover 18 pockets. A single-number bet pays more but wins far less often. The rule of thumb is simple: the payout is set so that the zero pocket remains unclaimed by any of the standard bets, and that unclaimed pocket is the operator's edge on the European layout.
What the red count does not tell you
Counting the red pockets answers a layout question, not a prediction question. A wheel that has just landed on red five times in a row is not more likely to land on black next. Each spin is an independent event on a fair wheel: the 37 pockets are equally likely on every spin, and the past sequence of colours changes nothing about the next outcome.
The red and black split also does not change between spins. The wheel is fixed; the probabilities are fixed. What varies is the short-run sequence, and short runs can look very far from the long-run average. A session of twenty spins can easily produce twelve reds and eight blacks without the wheel being defective. Over a very large number of spins, the share of red outcomes approaches its expected proportion, but no individual session is guaranteed to resemble that average.
Volatility in roulette comes from the bet type, not from the wheel. A single-number bet has high volatility: it pays rarely but pays a multiple of the stake when it hits. An even-money colour bet has lower volatility: it wins close to half the time, but each win only returns one unit of profit. Volatility does not change the RTP of either bet under the same rule set.
Procedural mistakes new players make at the table
The first mistake is betting after the window has closed. In a physical venue, the dealer announces the close, and a chip placed after that moment is either returned or treated as a late bet depending on house procedure. Online, the table simply stops accepting wagers, and a player who hesitates misses the spin. The fix is to decide your bet before the ball slows.
The second mistake is confusing the payout with the total returned. A winning even-money bet pays one unit of profit and returns your original stake, so a winning 10-unit bet on red returns 20 units total, of which 10 is profit. A player who expects to receive 20 units of profit on top of the stake has misread the payout.
The third mistake is assuming that a colour bet is a coin flip. It is close, but the zero is the difference, and it is the reason the bet loses slightly more often than it wins. Understanding that single pocket is the difference between playing with a clear picture of the arithmetic and playing on a mistaken one.
FAQ
Are there 18 red numbers on every roulette wheel?
Yes. Both the European wheel with 37 pockets and the American wheel with 38 pockets carry 18 red and 18 black numbers. The difference between the wheels is the number of green zero pockets, not the red count.
Does the zero count as red or black on a European wheel?
Neither. The single zero sits in a green pocket and is a losing outcome for red, black, odd, even, high and low bets. It is the pocket that gives the operator an edge on the even-money bets.
Why does a red bet pay even money when it does not win half the time?
Because the payout is set against the 37-pocket wheel, not against a 36-pocket wheel. There are 18 winning pockets and 19 losing ones, so the bet wins slightly less than half the time, and the even-money payout reflects that imbalance.
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