No. You can win on a given night, but the longer you play, the less likely you are to be ahead: after 100 spins on red, 36% of players are ahead; after 1,000, 19%; after 10,000, 3 in 1,000. The zero makes every bet pay back 97.30 cents per euro.
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The trick is the zero
A European wheel has 37 pockets: 1 to 36 and the zero. But prizes are paid as if there were only 36. Bet on a number and hit it, and you get 36 times your stake (35 in winnings plus your bet). For it to be fair, you would need 37.
That gap is the house edge: 1 in every 37 euros staked, or 2.70%. It applies equally to every bet on the table. There is no good bet and bad bet. They all cost the same.
One night, yes. A lifetime, no
The 2.70% is an average. Over a few spins, luck weighs far more than the edge, which is why plenty of people walk away ahead on a given night. Over time the opposite happens: luck evens out and the edge piles up.
The chart shows the share of players who are ahead after each number of spins. It is not a simulation: it is the exact probability.
The longer you play, the fewer people are ahead
Chance of being ahead after each number of spins, by type of bet. The horizontal axis grows tenfold at each step.
Wheel
Share of players who are ahead after each number of spins
On red (pays 1 to 1)
On a dozen (2 to 1)
On one number (35 to 1)
Spins
On red (pays 1 to 1)
On a dozen (2 to 1)
On one number (35 to 1)
Average loss
10 ≈ 0.3 h
34.4%
41.6%
24.0%
−€1
100 ≈ 2.9 h
35.5%
40.5%
50.9%
−€14
1,000 ≈ 29 h
18.8%
26.7%
45.1%
−€135
10,000 ≈ 286 h
0.3%
2.7%
32.5%
−€1,351
100,000 ≈ 2,857 h
0.0%
< 0.1%
7.3%
−€13,514
Betting on one number brings more surprises: many people stay ahead for longer, because a single hit pays 35 times. But the average loss is the same on every bet. Time is always on the house’s side.P(ahead) = P(W·(k+1) > n), W ~ Bin(n, c/37), computed exactly; the curve uses spin counts where a tie is impossible, and the table counts ties as not ahead. House edge: 1 − 36/37 = 2.70%. Hours at about 35 spins an hour at a live table.
The “tricks” going around
Betting systems. Doubling after a loss, raising and lowering stakes, following sequences. None of them changes what each bet costs. We go through the numbers in Does the martingale work?
Hot and cold numbers. The wheel has no memory. If 17 has not come up in 200 spins, it is no more likely now. You can check it by spinning a wheel in the simulator.
Faulty wheels. There were historical cases, like Joseph Jagger in Monte Carlo in 1873, who exploited an unbalanced wheel. Today wheels are inspected, and online roulette uses certified random number generators.
Roulette can be enjoyed as entertainment with a price tag. Believing you can beat it is the door to losing far more than you planned.
TechnicalWhy time works for the house
After n one-unit bets on red, the result has mean −n/37 and standard deviation ≈ √n. The expected loss grows with n and the spread with √n, so beyond some point the loss dominates. Under the normal approximation, the chance of being ahead drops below 2.5% once n/37 > 1.96 · √n, that is, n > (1.96 · 37)² ≈ 5,260 spins. The chart’s curves are exact: P(W · (k + 1) > n) with W ~ Binomial(n, c/37), computed in log space in src/lib/binomial.ts and checked against SciPy in the tests.
Related questions
What is the best bet in roulette?
On a European wheel every bet loses the same on average: 2.70% of the stake. Red, a dozen or a single number, it makes no difference. Only the swings change: on a single number you win rarely but big. In French roulette with the “la partage” rule, even-money bets lose half as much, 1.35%.
Is online roulette rigged?
It does not need to be. The zero already guarantees the house its share. In Spain, games from licensed operators go through a technical certification that includes the random number generator. The problem is not that it is rigged, but that it works exactly as advertised.
Does it help to track the numbers that come up?
No. The ball does not remember what came before. After ten reds in a row, the chance of red on the next spin is still 18 in 37. Believing otherwise is called the gambler’s fallacy, and it is one of the most studied mental traps.
Is European or American roulette better?
European, with a single zero, loses 2.70% of every bet. American has a double zero and loses 5.26%, almost twice as much. Its five-number bet (0, 00, 1, 2 and 3) is worse still: 7.89%.
How much do you lose playing roulette for an hour?
It depends on how much you bet and how fast you play. A live table runs about 35 spins an hour; at €5 a spin that is €175 staked and about €4.73 lost on average. Online or automated roulette runs much faster, and the loss per hour grows in proportion.