🎰 Roulette — red, black or green?
← Fun & RandomThe casino's wheel, with the zeros left in. Pick a colour, set a stake, and spin once or a hundred times: the count underneath keeps score of every pocket, and the money line shows what the house's edge takes out of it.
The spin
How the wheel is built
A roulette wheel is a numbered ring: 36 numbers from 1 to 36, half of them red and half black, plus the green zeros that belong to the house. Which wheel you are playing decides how many zeros are on it — and the zeros are the whole of the casino's edge, because every bet on the table is paid as though they were not there.
| Wheel | Pockets | Red | Black | Green | Edge |
|---|---|---|---|---|---|
| European — one zero | 37 | 18 · 48.6% | 18 · 48.6% | 1 · 2.7% | 2.70% |
| American — 0 and 00 | 38 | 18 · 47.4% | 18 · 47.4% | 2 · 5.3% | 5.26% |
| Triple zero — 0, 00 and 000 | 39 | 18 · 46.2% | 18 · 46.2% | 3 · 7.7% | 7.69% |
The pockets are not in numerical order. The wheel is built so that low and high numbers, odd and even, red and black all take turns round the rim, which is what makes the table look so scattered as the wheel turns. This page draws from the standard order, which changes with the wheel you pick:
The spin itself is the plainest draw there is — one pocket out of 37, 38 or 39, each of them equally likely:
pocket = floor(random() × pockets)
- The colours are the real ones. In 1–10 and 19–28 the odd numbers are red and the even ones black; in 11–18 and 29–36 the odd ones are black and the even ones red. That makes the numbers alternate red, black, red, black the whole way round, with the zeros sitting between two of them.
- Red and black pay 1 to 1: a $10 bet that wins comes back as $20, the stake and its twin.
- Green is every zero at once, so it is paid as the straight-up bets it really is: 35 to 1 with one green pocket (what any single number pays), 17 to 1 with two (the same as the 0–00 row bet) and 11 to 1 with three (the shape of a street bet). On the wheel you have chosen it is . Each of those returns 36 units whatever the wheel has, which is exactly what leaves the edge on the bet.
- The edge is the same on every bet on the layout: the number of green pockets divided by the number of pockets. Systems are sold on the idea that some bets are better than others; none of them changes that fraction.
Where these numbers come from
- The pocket orders — the single-zero, double-zero and triple-zero wheels — the colour of every number, the number of pockets and the 2.70% / 5.26% / 7.69% edges all come from the same article.
- What red, black and green pay, and how the edge is worked out, from its bet odds table and its house edge section.
- The half-back and en prison rules, which hold or halve an even-money bet that lands on a zero and so cut the edge to about 1.35% on a single-zero wheel and 2.63% on a double-zero one, are set out by the Wizard of Odds. This page does not play them: a colour bet that loses on a zero is simply lost here, which is the plainest version of the bet — and the one the edge above belongs to.
- The triple-zero wheel is a newer arrival: three green pockets on a rim that still carries the same 36 numbers, which is what makes it the most expensive of the three to play.
Nothing here pretends to be a physical wheel. The pocket is drawn at random rather than thrown by a ball, so every pocket is exactly as likely as every other one — which is the wheel at its fairest, and the only version of it that can be checked.
Frequently asked questions
So red is not 50/50?
No, and that is the whole game. There are 18 red pockets out of 37, which is 48.6%, not 18 out of 36. With 36 pockets and 18 reds, even money on red would be a fair bet; the 37th pocket, the green zero, is what turns it into one that loses slowly. A second zero takes red to 18 out of 38 (47.4%), a third to 18 out of 39 (46.2%), and the house's share grows with them.
Which wheel should I play?
The one with the fewest zeros. A spin costs 2.70% of the stake on a single-zero wheel, 5.26% on a double-zero wheel and 7.69% on a triple-zero one, so the three-zero table takes nearly three times as much per spin as the European one. If the table also offers en prison or half-back, where an even-money bet that lands on a zero is held or halved rather than lost, the edge on those bets falls to about 1.35% on a single-zero wheel.
Why does green pay so much more than red?
Because it wins so much less often. Red comes up 18 times in 37; a single zero comes up once. The payouts are the same shape of bet scaled to cover every zero — a single number at 35 to 1, the 0–00 row at 17 to 1, a three-pocket street at 11 to 1 — so the edge on green is exactly the edge on red. The big number on the card is the price of a rare event, not a better bet.
Is green a bet the table actually has?
Not as a printed colour bet. On a real layout you would put a chip on the zero itself, or on 0 and 00 together (the row, which pays 17 to 1). This page bundles every zero into one green bet and pays it at the odds the equivalent chips would pay, which is why those odds change when you change the wheel.
Six reds in a row — is black due?
No. Every spin is drawn from all the pockets again and the wheel has no memory of the last six. Six reds from a given point is 1 in 64 on a single-zero wheel, but a run has dozens of places it could start in a hundred spins, so runs turn up far more often than they feel like they should — and the next spin is still 18 in 37. Expecting black because red has had its turn is the gambler's fallacy, and it is the belief the table is happiest to see.
Can a system beat the wheel?
Not the arithmetic of it. Every bet on the layout is paid as though the zeros were not there, which is what makes the edge the same everywhere: no arrangement of stakes changes the fraction of the wheel that belongs to the house. What does change it is a physical bias in a real wheel, or a computer timing one — and neither can exist here, because this page draws the pocket at random rather than throwing a ball at it.
Is this real money?
No. There is no money, no account and no payment: the stake is a figure the page multiplies for you so that the edge is visible, and nothing is saved on your device or sent anywhere. It is a toy for watching what a hundred spins do, not gambling advice.
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