Roulette Probability Calculator

Calculate the exact probability of any roulette bet hitting on a single spin or over multiple spins. Understand streak probabilities and expected outcomes.

Formula:P(at least once in N spins) = 1 - (1 - p)^N

Per Spin Probability

2.70%

1 in 37.0

P(Win in 37 spins)

63.7%

Expected Appearances

1.00

in 37 spins

P(2 in a row)

0.073%

European has better odds

Type of bet to analyze

Calculate probability over this many spins

Probability Analysis for 1 Number

Single Spin

Win Probability:2.7027%
Odds:1 in 37.00
Fraction:1/37

Over 37 Spins

P(At Least 1 Win):63.71%
P(Zero Wins):36.29%
Expected Wins:1.00

Consecutive Win Probabilities

Probability of winning this bet multiple times in a row:

2 in a row
0.073%
3 in a row
0.0020%
5 in a row
0.000001%
10 in a row
0.0000000000%

Important: Independence of Spins

Each roulette spin is completely independent. If red has appeared 10 times in a row, the next spin still has the same probability of being red (~48.65% on European). The wheel has no memory. "Due numbers" and "hot numbers" are gambling fallacies.

Key Facts

  • •Each spin is independent - past results don't affect future outcomes
  • •European roulette has 37 pockets (0-36), American has 38 (0, 00)
  • •Single number probability: 2.70% European, 2.63% American
  • •Even-money bet probability: 48.65% European, 47.37% American
  • •The "law of large numbers" doesn't mean short-term results will balance

Frequently Asked Questions

What is the probability of hitting a single number in roulette?

On a European wheel, the probability is 1/37 (2.70%). On an American wheel, it's 1/38 (2.63%). Over 37 spins on a European wheel, you have about a 63.4% chance of seeing your number at least once.

How does the number of spins affect probability?

More spins increase the chance of your bet appearing at least once. However, each spin remains independent - previous results don't affect future spins. This is why "due numbers" is a myth.

What is the probability of red appearing 5 times in a row?

On a European wheel, P(red) = 18/37 ≈ 48.65%. Five reds in a row has probability (18/37)^5 ≈ 2.73%. This is rare but happens regularly in casinos across thousands of spins.

Can I use probability to beat roulette?

No. Understanding probability helps set realistic expectations but can't overcome the house edge. Each spin is independent, and the house edge remains constant regardless of betting patterns or history.