About Roulette

Roulette is a very popular casino game and it is available at all online casinos. It´s a game played with a ball and a big spinning wheel with numbers 0-36 written to it.

Roulette Rules

Player simply places bets on different numbers (one number or more), on even money bets (Black/Red, Even/Odd, 1-18/19-36), on any combined bets or a combination of all these. The roulette wheel is spun and exactly one number is selected at random between 0-36. If the number lands on selected bet, the player wins according to standard paytable. Bets on even money bets return 1:1. There is a special rule if the result is 0. In French Roulette the rule is called “La Partage” and half of the bets are returned on even money bets if the result is 0. This rule doesn’t apply to any other bets. If the result is 0, all other bets lose unless the player has made a bet on 0.

A bet placed on single number (Straight up bet) returns 36x bet. All other bets pay relative to the probability of the bet. For example a bet split between 4 numbers pays 9x bet because there is 1 in 9 chance (excluding zero) to hit any of those 4 numbers out of 36. To calculate the payout of your bet you divide 36 by the sum of numbers you placed a bet on. For example if you place similar bets on 12 different numbers, your winning bet will return 36/12 = 3xbet.

House Edge and Rule Variations

There are many different Roulette variations and each of these have a slightly different house edge.

European Roulette – Has one zero and 36 numbers. House edge is 1/37 = 2.70% on all bets made.

American Roulette – Has two zeros (0 and 00) and 36 numbers. House edge is 2/38 = 5.26% on all bets made.

French Roulette – Same as European Roulette but with La Partage rule (explained above). This reduces the house edge of even money bets (1:1 payouts) to 1.35%, making these bets the lowest house edge bets on Roulette. The casino softwares offering French Roulette are: Microgaming, Boss Media, Cryptologic (European VIP Roulette), Wagerworks and Chartwell.

French Roulette with En Prison rule – This is the same rule as “La Partage” but the player has the option to spin again and if the even money bet wins, he will receive back the full even money bet made previously. If the bet loses, the player loses the even money bet made previously. Since both outcomes happen with equal probability the house edge is exactly the same as with La Partage rule. Grand Virtual softwares offers this rule variation.

NetEnt software offers French Roulette but it doesn’t have La Partage rule meaning that the house edge is 2.70% on all bets.

Optimal Strategy

There is no other strategy to play Roulette than to choose a Roulette variation with lowest possible house edge. If all Roulette variations count for bonus wagering requirements, you should avoid American Roulette with two zeros and if French Roulette is available, play it with even money bets (La Partage rule) to minimize the overall house edge. However, even money bets have only 1:1 payout so if you want to make a high variance bet for a large payout, you’ll have to pay for 2.70% house edge.

Variance and Results Over Bonus Wagering Requirement

Roulette is often excluded from bonus wagering requirements because it is possible to bet simulatenously on opposite outcomes and reduce risk this way. However there are some bonuses where completing the wagering requirement on roulette results in lowest expected loss with minimal risk. The variance of Roulette depends on the type of bets made. For bonus wagering requirements the most typical bet is even money bet with “La Partage” rule which results in  0.99 standard deviation per spin. This is practically the same as a coin flip. The standard deviation of the end result after doing N spins on even money bets by betting B per spin is

STD DEV  = 0.99 * B * SQRT(N).

For example doing N = 100 spins betting on black with bet size B = 1 results in standard deviation 9.9.

When completing bonus wagering requirement on Roulette, the player typically wants to reduce the variance as much as possible. It is possible to reduce the standard deviation below 0.99 by betting simultaneously on both RED + EVEN or BLACK + ODD. This results in standard deviation 0.937 per unit wagered. So betting $1 on both RED+EVEN (or BLACK+ODD) would result in lower variance than betting 1€ on RED only.