Roulette Probability Calculator

If you are planning to play at roulette online with real money, it is imperative that you become familiar with the probability of winning in a game. Hence, you must know how the Roulette probability calculator works.

This is particularly important for roulette because each bet has a specific mathematical winning probability. The odds are impacted by the kind of roulette you will play and the rules applicable to it.

In this article, you will find the most asked questions about calculating the winning probability in a roulette online game.

The MOST asked questions about Roulette Probability Calculator
What is the probability of roulette wheel ❓

Roulette wheel has 37 fields (American one – 38). So, the probability of hitting one of them is 1/37 or 2.7%.

What is the probability of winning roulette ❓

Your winning probability may vary depending on your chosen bet type. If you would decide to pick only one number then you would have 2.7% chance of winning. However, if you would go for a Red/Black bet then you would have a 48.6% chance of winning and so on.

What are the roulette wheel probabilities ❓

If you would go for Even/Odd, Red/Black or Low/High bets then a probability of hitting is – 48.6%, Column and Dozen bets has a 32.4% probability of winning and a bet on a Single Number has a 2.7% chance of winning.

Why a chance of winning in American roulette is lower ❓

American roulette has 38 fields instead of 37 (additional 00). As a result, your chances of winning become lower.

Can you beat roulette ❓

Roulette is a game of luck after all and in the end casino will win. Always be aware and gamble only with money you can afford to lose.

Which roulette bet has the highest probability of winning ❓

Red/Black, Even/Odd and Low/High bets has a highest chance of winning – 48.6%.

Which roulette bet has the lowest probability of winning ❓

A bet on a single number has the lowest chance of winning – 2.7%. However, it has the highest payout – 35 to 1.

You must also know that there is the gambler’s illusion: Red or Black? Casinos promote this illusion. That is why casinos show the statistics of past spins. Those statistics do not have a practical value, and they cannot be used as a guide to predict upcoming numbers and their colours. The roulette novices must know that each number is on a specific colour.

There are answers to important questions that are asked about roulette, which you must also take note of.

roulette wheel transparentHow to Calculate Probability in Roulette?

The roulette wheel has 37 equally sized spaces. Since this is the case, the ball will most likely land equally in any space. That means a roulette’s probability distribution is equal. This is different from American roulette probability because their wheel has 38 spaces.

These are the values that need to be calculated:

  • Since there are 37 spaces, the probability of a ball landing on one of them is 1/37.
  • There are 18 red spaces 18, so the chance of a ball landing on a red is 18/37.
  • The black or green spaces equal 20, so the probability that the ball will not land on red is 20/37.

If you bet 1€ on red, and the ball lands on red, you will win it back, and the amount is doubled, so you profit 1€. If you bet 2€ on red, but the ball lands on green or black, you will lose your bet (-2).

Here, ”A” is used as the variable for the calculation to represent your winnings in roulette from red that takes the value of 2€. The probability is 18/37 and will take the -2 value with 20/37 probability. Here is how you should do the roulette probability formula:

P(Red) x A (value for red) + P(Not red) x A (value that is not red) = 18/37 + 2 + 20/37x (-1) = 0.4865.

Roulette Probability Calculator

roulette wheel transparentInterpreting the results of the probability roulette calculator:

You must remember that the expected value’s meaning is used to interpret the results. The value you can expect is like the average measurement. It is an indication of what will happen each time you bet 2€.

Even if you win multiple times consecutively, you will averagely lose 5 cents in the long run while you play. The house advantage comes from the 0 and 00. This is a very small advantage, making it hard to detect, but the house will always win at the end of your game.

You must know that the true odds represent the probability of roulette outcome, rather than the possibility. However, the casino is not going to pay out winnings based on true odds. The winning bets are paid using the 1:35 odds, and the even money wagers have a 1:1 payout. This is because of that one zero pocket.

roulette wheel transparentWhat is the Probability of Winning at a Roulette Wheel?

These bets are quite different, and they are exclusive to French/European roulette only. The numbers in this wheel are combined based on the roulette wheel’s position instead of the table. There are two kinds – fixed and variable.

Zero’s neighbours – These are bets that cover 17 numbers, and all of those are near green zero. You would have to put at least nine chips so that all those numbers are covered, and you will have winning odds of 45.9%. There is no fixed payout, and it can be as high as 24:1, which depends on the number that wins. This is also called “the grand series.”

European roulette - probabilities in roulette

Wheel thirds – These are the 12 numbers that are directly situated from across neighbours of Zero. This has a probability of 32.4%, with a payout that is set at 17:1. This is quite like dozen/column bets when it comes to the odd terms and payout.

Zero Game – This is a smaller version of neighbours of Zero. It covers only seven numbers that are closest to slot green zero. There is an 18.9% bet winning odds here, and the payout could be up to 26:1.

The Orphans – The bet that covers the remaining numbers that were not yet mentioned. There is a 21.6% chance of winning this bet, and payouts can be 35:1 or 17:1.

These are fixed call bets. Your variables here are the neighbours where you will place bets on five neighbouring numbers, and your winnings are at 13.5%. The remaining variable is called the ‘finals’ where your bet is on the last digit. Based on the numbers, there is an 8.1% and 10.8% probability.

The European table only contains one zero, and this is a big difference to players. European roulette odds have better odds since there is only one pocket that could make the round fail. That also means there is a smaller house edge in a European roulette compared to American roulette that has 0 and 00.

Some roulette games in Europe have more rules that are more helpful to the player in beating the house edge. If a casino is offering a la partage, that means you are only using half of your even money bet in case the ball lands in zero. The probability of winning a roulette wheel cannot really be predicted because the previous sequences do not impact the current one.

roulette wheel transparentWhat is the Highest Roulette Odds Probability?

You only have one chance of winning and 37 ways of losing the bet. That means your probabilities in roulette odds are 37 to one, and this makes it a thrill. Calculate odds with roulette odds calculator online.

In order to understand this in terms of money, you must realize that the winner’s payoff is not 36:1 roulette odds because it will be a fair game. It is rather 35:1. The casino will short you out by two units because the casino will not make a profit if it pays odds fairly. Thirty-six will be divided into two and times 100 to reveal a house edge of 5.26%. Hence, roulette odds do not reflect actual roulette payouts. If you check a roulette probability chart, you will see the probability for each set of numbers.

Odds for Success:

Even, odd, black, red, 1-18, and 19-36 all have a probability of 48.6% if the payout is 1:1.

1-12, 13-24, and 25-36 have a probability of 32.4% if the payout is 2:1.

Single number with a payout of 35:1 have a probability of 2.7%.

Two numbers with a 17:1 payout have a 5.4% probability.

Three-number combo with an 11:1 payout has an 8.1% probability.

Four-number combo with an 8:1 payout has a 10.8% probability.

Six-number combo with a 5:1 payout has a probability of 16.2%.

You can use these statistics when you try the roulette wheel probability calculator, but it does not guarantee anything.

American roulette probability chart

roulette wheel transparentHow to Use Probability When Playing Roulette?

You can beat roulette by improving the probability of your odds. Roulette is famous for being a tricky game, and that is because of the huge house edge it has. There is no solution to how you can win roulette each time it spins. However, if you want to maximize your winning potential, you would have to use the odds wisely. Even if it is really based on luck, you can do a couple of things to increase your chances of winning a nice payout.

roulette wheel transparentYou must know your odds

The odds that are placed in bets vary greatly, so if you want to maximize your bankroll, you need to know your odds.

If you use a probability roulette wheel in a game, you can find out if you can beat the math in your game.

A system could combine the playing and money management strategy. If you have enough bankroll, you can increase your chance of winning by doubling your bet after each loss, and you will not reach the table limit, which you can easily do. However, this is not really a guarantee.

Whatever your strategy is, they could suffer in the same way. Assuming all wheel numbers have the same probability, which means there is no bias. The math would mean the casino always wins. The system might look great, and it works short term, but if it lands on a number you did not bet on, you are going to lose. The casino will move to winning with a house edge of 2.7% or 5.26%.

There are systems that involve betting on a lot of numbers, like 20. If this is the case, you will win more often because you are betting on most of the numbers. However, if none of them turn up, you will lose all bets. This could wipe out your wins.

Probability in Roulette Wheel

roulette wheel transparentWhat is the Probability of Red in Roulette?

If the ball lands on red, you win 1€. Then, the next step is to bet 1€ on black. Always change the colour when you win. If it’s black, you will lose the first 1€. Then bet 2€ on red. If you lose, you stay in red and double your bet until you win. For instance, losing 1€, you must bet 2€ on red; if you lose again, bet 4€; another loss, bet 8€ on red. When you win, change to black and bet 1€.

If zero comes up, which rarely happens, you lose your 1€. Then, bet 2€ on red again, and keep doing this until you win before you can change colour.

There are 37 numbers on the wheel. There are 18 blacks and 18 reds. Therefore, the winning odds of red are 18/37, which is 0.4865. The odds of black are the same. The same goes for any “even chance” bet that includes highs and lows, and evens and odds. The odds are not changing, no matter how many times red or black have appeared in a row. Consider your loss when you bet on black. What you do not realize is that the odds of red or black coming up is not affected by any sequence. This is the case in all losing roulette online game.

The calculation is very simple. There are no changes except for the amount that you made a bet on. You are either lucky, and you could win back what you lost, or lose it all. The casino owner does not care if you win because they know there is always a loser in every win. If you think about it, there are more losses than wins.

roulette wheel transparentWhat is the Probability of Black in Roulette?

Since each spin is a new event, black can come up with the same probability as red anytime during the play, no matter how many times each colour wins. Particularly with European roulette where there are 18 blacks, 18 reds, one zero. American roulette has two zeros, which is not good for your winning chances. Hence, the probability of black is 18/37 = 0.4765 or 48.65%.

Black and red have the same probability, which seems paradoxical, and it is expected that the colour changes fast. It could be from a probability point that it is senseless to assume the colour that has not won for a long time could most likely appear now.

roulette wheel transparentAmerican vs. European Roulette

Anyone who is trying to figure out the difference between American and European roulette must understand the double and single zeros, watch roulette rules in 6 min video. The American version has double zeros. In the European roulette, the croupier spins the reel with 37 pockets, and the small ball falls into one when the spinning stops. Any number on the wheel has an odds of 35/1, and if you succeed, you earn your bet back. That means the house edge is 2.7% and the RTP rate is 97.3%

The American roulette wheel is the same, but it has an extra pocket – double zero. The same principle is applicable when you bet on a pocket the ball falls into, and each number has an odds of 35/1. Your stake is given back to you if your bet succeeds. However, even if the odds are the same, your chance of succeeding becomes less because of the extra pocket. Hence, the house edge is 5.26%, and the RTP is 94.74%. Therefore, you have a bigger chance of winning if you play European roulette.

Roulette Wheel Probability Calculator

roulette wheel transparentThe House Edge Difference

Even if there is only a subtle difference, and it may look irrelevant, it has a huge impact on how your games will turn out.

When there are lower odds, there are bigger payouts. However, as logical as it may be, it is not the same with American roulette. Even if the odds are lower, if you bet on a winning number, you will also get paid 35:1, which is the same in European roulette.

roulette wheel transparentThe Return to Player (RTP) Percentage

In roulette, it is essential to take note that this is theoretical because it is based on what is returned to a player on hundreds of spins, and all kinds of bets are available.

You could get great results by just spinning a few lucky spins, or you might not win at all. Players who focus on making Even Money bets such as Black or Red receive more winning bets compared to players who just choose their favourites. However, the odds are only suggesting that.

If you want to consistently win in roulette, you must not base your chances on the sequences and patterns. It is sensible to see 1,2,3 spinning patterns, but that is not different from 31,8,15 spinning. The betting progression does not change except for the amount. You can only beat roulette if you can change the winning odds. You must also take note of the differences between American and European roulette because it can greatly affect your winning chances. Therefore, it is important to know how the Roulette probability calculator works.

Zigmas Pekarskas

Written by:

Casino card games and poker expert

Founder and CEO of also well known poker professional player, with more then 15 years of playing poker and other card games. 10 years of writing articles, doing reviews of poker rooms and teaching other poker players how to improve their game.