Roulette Winning Formula

Roulette Winning Formula

Roulette has remained one of the most popular games in any land-based or online casino for over a hundred years. It attracts millions of players worldwide, many of whom believe they can make a quick and easy profit. However, this is not so simple, as the roulette winning formula in the USA has specific probabilities. No strategy or tactic can guarantee a result, but you can easily minimize your risks, and the first step is to understand the odds and probabilities.

Probability in Roulette Games

Probability is the chance that a random event will happen; it can be expressed as a fraction or a percentage. The higher it is, the greater the chances, and it is essential in terms of understanding the prospects of each specific roulette bet.

In this game, the number of potential outcomes is fixed, and no one can change it, so it is quite simple to calculate the odds. To do this, you can divide the number of ways to win by the total number of outcomes.

If you do this for each possible bet, it becomes clear that your probability of winning cannot be 50/50 because of the casino’s mathematical advantage. It is called house edge, embedded in the game rules and enforced by the Zero sector, which does not bring payouts on most bets.

European Roulette uses one Zero sector, and there are two of them in the American version.

Another important factor is the randomness of the results and their incoherence; only luck affects the outcome of each round. Keep in mind that even if a red sector comes up 5 times in a row, it doesn’t increase the probability of seeing a black sector after the next spin — you cannot rely on previous results while counting odds.

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Roulette Bets and Regulations

One of the main advantages of any roulette version is simple rules with the main features always remaining the same:

  • Participants make their bets, placing chips in different sectors of the playing field.
  • The wheel spins. In regular mode, you launch the spins yourself, but in live mode, it is done by the dealer or a special device.
  • Results are determined. Winners receive payouts, and then the next round starts.

These steps remain the same even if you play a non-standard roulette version.

Roulette bets
On each chip, you can see its casino value

The online roulette winning formula does not change, and it does not depend on the roulette type. With every version, payouts occur when you guess where the ball will stop.

Roulette Betting Odds and Payouts

All bets are divided into internal and external, and the first is riskier but brings large payouts, while the second allows you to reduce risks, but the prizes with them are also smaller.

Straight UpSingle bet on one number35:1
SplitTwo numbers located next to each other17:1
BasketThree numbers along with a Zero, for example, 0, 1, 211:1
StreetLine of three horizontal numbers11:1
CornerFour neighboring numbers8:1
Six LineTwo streets (six numbers)5:1
Column12 numbers along a vertical line2:1
DozenNumbers 1 to 12, 13 to 24, and 25 to 362:1
Odd/EvenAll even or odd numbers1:1
Red/BlackBet on color1:1
High/LowThe number will be greater 18 or less 181:1

A riskier bet brings larger payouts, but it can take a lot of time to get it. Remember that the casino house edge remains the same regardless of the bets you prefer.

How to Calculate Roulette Odds

This table game is based on the theory of probability, so it is easy to calculate the theoretical chance of any possible outcome. To do this, you can divide the total number of winning outcomes by all possible outcomes and multiply the result by 100 to get the percentage probability.

For example, if you bet on Odd/Even, Red/Black, or High/Low, the chances of winning are 18/37 х 100 = 48.64%. In American Roulette, the probability is 18/38 x 100 = 47.37% due to two Zero sectors.

The casino house edge may seem small, but it brings a lot of profit to casinos in the long run.

This way, you can calculate the probability of any outcome and find a chance of getting several desired results in a row.

Consecutive Numbers

A common mistake for beginners is to believe that previous results affect future ones. New players often think that if, for example, a black number comes up 4 times in a row, the probability of it appearing the fifth time decreases. It does not work this way, as results are not connected, and the chance that a black number will come up next is always 48.64%. If you initially plan your bets for several rounds, you need to calculate the probability using a different method.

For example, you want to choose one number three times in a row. The probability of this outcome in one round is 1/37. As for two times, it is 1/37 x 1/37 = 1/1369 or 0.073% and for three times in a row it is 1/37 x 1/37 x 1/37 = 1/50.653 or 0.00197%.


Calculating series’ probabilities in the roulette winning odds formula applies to bets on equal odds, as in Odd/Even, Red/Black, or High/Low. In this case, you assume that one of these results will appear several times in a row. The formula is similar, but the odds change — since they are much higher for each specific outcome, the final probability is also significantly higher.

Roulette bets
Equal odds bets have the highest probability

For example, you want to know the probability of a black number appearing three times in a row. To do this, you can take the initial probability of 18/37 and multiply it by the same fraction twice, and the result is 18/37 x 18/37 x 18/37 = 1/8.68, meaning the chances of getting this result are 11.52%.

Roulette Strategies & Systems

Although this table game works based on the probability theory, it is hard to use any strategies effectively due to the house edge. Most tactics are designed for equal odds, but the Zero sector makes your chances less than 50%.

Casinos still stay in the black in the long run, but during a specific gaming session, you can beat a gambling venue using strategies.

The most popular and easy to master is the Martingale system, and it works as follows:

  • You bet on Even/Odd.
  • If you win, switch your choice but bet the same number of chips.
  • If you lose, double the number of chips and repeat your bet.
  • Do this until your next payout and repeat.

This strategy allows you to compensate for all previous losses and make a small profit with just one winning spin. However, due to the geometric progression used, you may lose your bankroll before getting your desired result, so it is better to bet the minimum number of chips from the beginning.

Features of Different Roulette Types

Roulette was invented over 150 years ago, and its basic rules have not changed much since then. Some casinos offer unique game varieties with additional options to win, and they are rather exciting, but the two basic versions of the rules remain the most popular.

European Roulette Winning Formula

This is the most common version of the rules. The European roulette winning formula considers only one Zero sector, and the total number of numbers on the wheel is 37, leading to a house edge of only 2.7%. There are also call bets, which allow you to choose unique combinations of numbers. To determine your winning chances, you can divide the number of sectors you bet on by 37.

Probability Formula of Winning in American Roulette

When this table game crossed the ocean and came to the USA, local casinos felt that the 2.7% house edge was not enough for them and added one more Zero sector, which increased the house edge to 5.24%.

Double Zero
There are two Zero sectors in American Roulette

The probability formula of winning in American roulette accounts for all 38 numbers, so the odds of winning for each outcome are lower than in European Roulette. Here, you need to divide the winning numbers by 38 to determine the probability.

How to Discover Roulette Winning Formula

You cannot influence the likelihood of receiving payouts in this or other casino games, but you can reduce risks. To do this, it is necessary to follow a few recommendations.

Place Many Bets

The number of bets you can make simultaneously is not limited, as you can place chips in different sectors of the playing field, with bets placed on different combinations allowing you to increase your chances of winning.

Use Multiple Corner Bets

Corner is one of the most profitable bets when comparing riskiness and potential payout. The payout ratio is 8 to 1, allowing you to place 7 bets at once, so you can cover most of the field and get a profit if at least one of the bets wins.

Change the Bet Size Gradually

We do not recommend you to increase the betting amount sharply to quickly compensate for all previous losses. Add chips gradually, reducing the risk of rapidly losing your bankroll.

Apply Money Management

Depending on your preferred bet type, you should have enough money for at least 10-20 risk-free predictions or 30-40 risky outcomes. Spending all your money at once is very dangerous, so use bankroll management even if you do not have too much money.

Use Statistics

In most slots and live games, it makes sense to check your history of previous spins, as this may allow you to make a better bet considering the probabilities of consecutive numbers and series. Still, do not forget that previous results do not affect further ones.


The formula for winning roulette for US players is the same for gamblers from any country, and it only depends on the roulette version.

These outcomes win about 50% of the time, namely Odd/Even, Red/Black, and High/Low.

In this game version, one wheel spin follows immediately after another, and you have less time for placing bets.

Many casinos provide demo versions of slots; with them, you can play for virtual chips without risking your funds. Keep in mind that demo mode is not provided in Live Casino.

Even if the odds of winning for these outcomes differ, you can still multiply them by each other.

Publication Author
Ashton Stewart
Author of articles
Ashton was born and raised in the USA. In 2012 he entered The University & Jepson Herbaria, University of California, Berkeley, and graduated in 2017. There he got acquainted with gambling and realized that there was not enough information about reliable websites on the Internet.
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