Roulette probability comes down to one fraction: the pockets that win your bet divided by all the pockets on the wheel. Red owns 18 out of 37 slots on a European wheel, which means it lands 48.65% of the time. A lone number covers 1 of 37, so 2.70%. Everything else on this page grows from that fraction, including green, streaks and what happens over a whole evening of spins.
At the table
One number
2.70% single zero (1 in 37), 2.63% double zero (1 in 38).Red or black
48.65% single zero, 47.37% double zero.Green
2.70% single zero, 5.26% double zero, 7.69% triple zero.Dozen or column
32.43% single zero, 31.58% double zero.Memory
None. Each spin starts from the same odds.
Roulette probability for every outcome
The table counts winning pockets for each kind of result and turns them into a percentage on the three wheels you might meet. Read across a row to see how each extra zero chips away at your chance.
| Result you need | Winning pockets | 0 wheel | 0 and 00 wheel | 0, 00, 000 wheel |
|---|---|---|---|---|
| A chosen number | 1 | 2.70% | 2.63% | 2.56% |
| Any green pocket | 1, 2 or 3 | 2.70% | 5.26% | 7.69% |
| A dozen or a column | 12 | 32.43% | 31.58% | 30.77% |
| Red, black or another 1 to 1 box | 18 | 48.65% | 47.37% | 46.15% |
Notice that no even money bet reaches 50%. A green pocket counts as none of those 1 to 1 choices, so it sits outside all of them. That missing slice is the house edge, and the payouts and odds guide shows how it shapes every payout.
What are the odds of hitting green?
Green means a zero pocket. A European wheel has just one of them among 37, so 2.70%. The American wheel has 0 and 00, so 2 in 38, or 5.26%. Three greens out of 39 pockets, the triple zero setup, works out to 7.69%.
Over several spins the chance of seeing green at least once climbs fast. Within 10 spins it reaches 23.97% with one zero and 41.76% with two. Flip it around and the numbers surprise people too: across 37 single zero spins, there is still a 36.29% chance zero never shows at all. Short sessions are lumpy. That is normal, not a sign of anything wrong.
More on the green pockets, and why they pay 35 to 1 when you bet on them directly, is on the roulette green page.
How to use the streak calculator above
The calculator above answers the "what are the chances" questions that come up at every table.
- Pick the wheel: European or American.
- Pick the outcome you care about, from a color or a dozen down to one number or zero.
- Type how many spins you want to look at.
- Read three answers: the chance it shows at least once, the chance it comes up every single time in a row, and the average count you should expect.
Worked example. Choose red on a European wheel and enter 5 spins. Red shows up at least once 96.43% of the time. Five reds in a row is 2.72%, which is about 1 in 37. The average count is 2.43 reds. Now switch to American: five in a row drops to 2.38%. Try one number and 37 spins next, and you will see the chance of catching it at least once is only 63.71%.
How many spins does it take to hit one number?
On average, a given number shows once per 37 spins on the European wheel and once per 38 on the American. Average is not a promise. The table shows the real chance of seeing your number at least once.
| Spins watched | Single zero | Double zero |
|---|---|---|
| 10 | 23.97% | 23.41% |
| 20 | 42.19% | 41.34% |
| 37 | 63.71% | 62.72% |
| 50 | 74.59% | 73.64% |
| 100 | 93.54% | 93.05% |
The math is simple. The chance of missing on one spin is 36 in 37. Multiply that by itself once per spin, then subtract the result from 1. Even after 100 European spins, your number is still missing in about 6.46% of cases.
Every spin is independent
A roulette wheel holds no memory. The ball does not know that black came up four times, and the pockets do not take turns. Each spin begins with exactly the same chances as the one before it.
Streaks still happen, and more often than people guess. Ten straight reds with one zero is 18 in 37 multiplied by itself ten times, roughly 1 in 1,347. A busy table spins thousands of times a month, so somebody sees a run like that fairly often. Here is the part that matters: after those ten reds, the chance of red on spin eleven is still 48.65%. Black is not owed anything.
The is roulette rigged page looks at why long streaks feel suspicious, and the wheel spinner lets you run 1,000 spins and watch random clusters form on their own.
Your odds of being ahead over a session
One spin of red is close to a coin toss. Many spins are not. Using flat 1 unit bets on red, here is the chance you finish with more wins than losses.
| Bets placed | Single zero | Double zero |
|---|---|---|
| 10 | 34.42% | 31.41% |
| 100 | 35.53% | 26.50% |
| 1,000 | 18.76% | 4.48% |
In 10 bets a tie of 5 wins and 5 losses is common, which is why that row looks low. The pattern is the point: the longer you play, the more the edge shows up. On a double zero wheel, fewer than 1 player in 20 is ahead after 1,000 even money bets.
Highest chance of winning at roulette versus best value
The highest chance of winning a single bet comes from the even money boxes, at 48.65% on a European table. That is a higher hit rate, not a better deal. Every bet on that wheel keeps the same 2.70% of your stake over time, because the payouts shrink as the chance grows.
So the best move is choosing the wheel. One zero gives every bet better odds than two, and French rules with la partage cut the even money edge to about 1.35%. If you are wondering how roulette stacks up against the rest of the casino floor, the best odds across the casino ranking compares it with blackjack, craps and baccarat. To price a specific bet, use the payout calculator.
Questions players ask
What are the odds of hitting green in roulette?
Expect green on 2.70% of spins with one zero, 5.26% with a pair of zeros, and 7.69% with three. In plain counts that is 1 in 37, 2 in 38 and 3 in 39.
What are the odds of winning roulette red or black?
Red or black hits 48.65% of spins on European wheels and 47.37% on American ones. It is never a true 50% because the zero pockets count against it.
What are the odds of hitting a number in roulette?
A chosen number averages one hit every 37 spins on the European game (2.70%) and every 38 on the American (2.63%). Over 37 spins the chance it shows at least once is about 63.71%, not 100%.
What are the odds on double zero roulette?
With 38 pockets, one number is 2.63%, red or black 47.37%, a dozen 31.58% and green 5.26%. Every payout matches the single zero game, so the house keeps 5.26% instead of 2.70%.
Does a long run of red make black more likely?
No. The wheel has no memory, so after any run the next spin has the same odds as always. On a single zero wheel black stays at 48.65% whether red came up once or ten times.
Which roulette bet gives the highest chance of winning?
Bets that pay 1 to 1 hit most often, close to half the time. They pay only 1 to 1, so over time they cost the same share of your stake as any other bet on that wheel.