Like nearly all casino games, roulette is a game of probabilities – every time the wheel is spun and the ball is launched, there is the exact same chance of something happening. Regardless of where the ball landed previously, the probabilities are still the same. Obviously there are several wagers in the roulette table that are more likely to come up than others, and it is important to understand the probabilities are in roulette so you can identify the bets where there is less value and avoid them, or alter your betting accordingly. The probabilities in roulette also depend on whether an American roulette wheel is being used, or a European roulette wheel, as an American roulette wheel has 38 numbers compared to a European wheel’s 37 numbers.
Single number (eg 1, 15 or 30 etc) – 2.7% (or a 36-1 chance)
Split number (eg 1 &2 , 33 & 36 etc.) – 5.4% (or an 17.5-1 chance)
Street bet (eg 4, 5 & 6 or 10, 11 & 12 etc) – 8.1% (or an 11.3-1 chance)
Corner bet (eg 1, 2, 4 & 5 or 13, 14, 16 & 17 etc) – 10.8% (or an 8.25-1 chance)
Six line bet (eg 1, 2, 3, 4, 5 & 6 or 19, 20, 21, 22, 23 & 24 etc) – 16.2% (or a 5.2-1 chance)
Dozen bet (eg 1-12, 13-24 or 25-36) – 32.4% (or a 2.1-1 chance)
Column bet (eg 1st column of numbers, 2nd column or 3rd column) – 32.4% (or a 2.1-1 chance)
Red or black – 48.6% (or a 1.1-1 chance)
Odd or even – 48.6% (or a 1.1-1 chance)
1-18 or 19-36 – 48.6% (or a 1.1-1 chance)
Single number (eg 1, 15 or 30 etc)) – 2.63% (or a 37-1 chance)
Split number (eg 1 &2 , 33 & 36 etc.) – 5.26% (or an 18-1 chance)
Street bet (eg 4, 5 & 6 or 10, 11 & 12 etc) – 7.89% (or an 11.7-1 chance)
Corner bet (eg 1, 2, 4 & 5 or 13, 14, 16 & 17 etc) – 10.53% (or an 8.5-1 chance)
Six line bet (eg 1, 2, 3, 4, 5 & 6 or 19, 20, 21, 22, 23 & 24 etc) – 15.79% (or a 5.3-1 chance)
Dozen bet (eg 1-12, 13-24 or 25-36) – 31.58% (or a 2.2-1 chance)
Column bet (eg 1st column of numbers, 2nd column or 3rd column) – 31.58% (or a 2.2-1 chance)
Red or black – 47.37% (or a 1.1-1 chance)
Odd or even – 47.37% (or a 1.1-1 chance)
1-18 or 19-36 – 47.37% (or a 1.1-1 chance)
As you can see, the percentage probabilities for the higher payout bets do not vary too much between American roulette and European roulette (a mere fraction for each one). But as the bets move closer to a 50-50 chance, the percentage varies a bit more between the two forms of roulette. The other thing you can see is that every bet on the American roulette wheel has less of a chance of landing than every bet on the European roulette wheel. Of course, this is due to the fact that the American roulette wheel has one extra number on it.
So, weighing it all up, you are more likely to win when playing European roulette, regardless of what you bet on than you are when playing American roulette. Which means that if you are given the choice of playing American roulette or European roulette, you should always be choosing to play the game with only the single 0 as opposed to the single 0 and the double 0.
The other thing you can work out the probability of is one number coming out a certain amount of times in a row. In American roulette, to work out a number coming up once, you divide 1 by 37. If you want to work out a number coming up five times in a row, you do the following – (1/37)*(1/37)*(1/37)*(1/37)*(1/37). This give you a percentage of 0.0000000144%. You can do this for any number of times in a row, you just add to the progression. However, as you can see, even the same number coming up a few times in a row has a low percentage. That is not to say it does not happen, because it does, but you are not likely to see it happening all that often.
When you break it all down into figures, roulette is an incredibly simple game. So all you have to do is keep the probabilities in mind when you are deciding on your next bet to work out the best value for you.PlayRoulette.org » For Dummies » Probabilities