Roulette Odds Calculator

Roulette Odds and Probabilities Guide

It is clear to everyone by now that roulette is a game of luck, not skill. But despite the luck factor, there is math behind every spin of the roulette wheel. So, each bet has its own odds and probability, which differ between roulette versions. In the sections below, we break down what odds and probability really mean and how to interpret them when playing different roulette variations.

Odds and Probabilities Chart of Roulette Bets

As we indicated above, the probabilities and odds for each bet and version will differ. So you don't have to look these values up, we have prepared a table below. Then we will explain the origin of these values and help you understand them.

Bet	Probabilities(single zero)	Probabilities(double zero)	Odds(single zero)	Odds(double zero)
Straight up	2.70%	2.60%	1:36	1:37
Split	5.40%	5.30%	2:35	2:36
Street	8.10%	7.90%	3:34	3:35
Corner	10.80%	10.50%	4:37	4:34
Basket	-	13.20%	-	5:33
Six Line	16.20%	15.80%	6:31	6:32
Column	32.40%	31.60%	12:25	12:26
Dozen	32.40%	31.60%	12:25	12:26
Even/Odd	48.60%	47.40%	18:19	18:20
Red/Black	48.60%	47.40%	18:19	18:20
High/Low	48.60%	47.40%	18:19	18:20

As you may have noticed in the table, the probabilities for roulette with one zero (European) are higher than for roulette with two zeros (American roulette table). Moreover, the difference becomes more noticeable as the bet covers more numbers. For example, for straight-ups, this probability difference is only 0.1%, since only one number is covered, and for even money bets (covering 18 numbers), the difference is 1.2%.

NOTE! As we mentioned, we use two terms: probability and odds. In short, probability and odds are two different ways of expressing the chances of an event occurring. In the context of roulette, such an event is a win.

The probability of winning is displayed as a percentage value and denotes the probability of winning for a given outcome.
Odds are the ratio of the probability of winning to the probability of losing.

How to Calculate Roulette Probability and Odds?

Now, most of you are probably wondering how to figure out the probability of each wager succeeding. Well, you do that by simply dividing the numbers that are covered by your bet by the total numbers on the roulette wheel and then multiplying by 100. This is how you arrive at the percentage and chance you have to actually win a wager. Let’s look at this in practice.

European roulette has 37 numbers, from 0 to 36.
If you bet on a straight bet (a single number), you have a 1/37*100 chance of winning.
This means that your chance is 1/37 = 0.0270
Once you multiply by 100, your chance of winning is calculated as 2.7%.

Another example here is the even/odds bet. This bet covers 18 numbers, and as a result, you do:

18/37*100 = 48.64% to win

We've figured out the probabilities, but how to calculate the odds? Here, too, everything is quite simple; you need to divide the number of winning outcomes by the number of losing outcomes. For example:

There are 37 numbers in European roulette.
A dozen bet covers 12 numbers.
Accordingly, the number of losing outcomes is 37 - 12 = 25.
So, the odds for a dozen are 12:25.
This means that, on average, for every 12 wins, there are 25 losses.

These examples are based on the European layout of the game. What this means is that there is a single zero in the game. If you were playing a double-zero variant, such as American Roulette, then you need to make the adjustments yourself. We have written out the formulas below in their simplified versions; you need to substitute the necessary values.

Odds

Number of Winning Outcomes Number of Losing Outcomes

Number of Winning Outcomes - total number of numbers covered
Number of Losing Outcomes - total number of uncovered numbers

Probabilities

Number Of Covered Numbers Total Number Of Numbers

100

Total number of numbers = 37 for single zero roulette
Total number of numbers = 38 for double zero

How to Calculate Roulette Probabilities for Complex Bets

We understand perfectly well that most players do not make only one type of bet, but combine them. Therefore, let's also consider the option of a complex combined bet and how to calculate its probability. For example, a player bets on the 1st dozen. Within the 2nd dozen, he bets five straight-ups. And within the 3rd dozen, he makes three splits. All this happens at the European roulette table. So:

There are 37 numbers in European roulette.
A bet on 1st dozen covers 12 numbers.
Five straight-ups in the 2nd dozen cover five numbers.
Three splits in the 3rd dozen cover another six numbers.
So, the total number of covered numbers is 12 + 5 + 6 = 23.
Now, we divide 23 by the total number of numbers in European roulette: 23/37 = 0.6216.
We convert to percentages by multiplying by 100. The probability of such a bet will be 62.16%.

In the context of odds, they will be equal to 23:14. So, for every 23 winning situations, there will be 14 losing ones.

Note! However, remember that if you use complex bets in combinations in which bets that cover fewer numbers are placed within bets that cover more numbers, then the probabilities and odds should be calculated based on the maximum value of the covered numbers. If we take the previous situation, but in it, all bets are placed within the 1st dozen, i.e. five straight-ups and three splits, then, since the 1st dozen covers 12 numbers, the probability will be (12/37) x 100 = 32.43%. And the odds will be 12:25.

What are the odds and probabilities of announced bets

The odds of Announced Bets, or French Bets as they are known, will differ. These bets may cover multiple numbers or even half of the wheel. Depending on whether you bet on Tiers du Cylindre, Jeu 0 Bets, or Voisins du Zero, you may have a different percentage. Check out the table below: