If you weren’t aware already, the house edge (also known as the expected value) is the reason casinos make a profit. It represent the percentage a player will lose on a given bet over the long term (and we’re talking infinity here, not just a couple of sessions at the blackjack table). To calculate the house edge for roulette, you must first establish the type of roulette you are playing, as the American game has 38 numbers (including zero and double zero) but pays out at 35/1 for hitting a single number. The European version, meanwhile, has 37 numbers, but still pays out at 35/1 for hitting one number.
So, in calculating the house edge for American roulette, you use the following figures: (−1×37⁄38) + (35×1⁄38) = −0.0526, giving you a house edge of 5.26%.
The house edge for European roulette, meanwhile, is calculated thus: (−1×36⁄37) + (35×1/37) = −0.0270, giving you a far more favorable house edge of 2.70%, just about half that of the American version.
In effect it is the presence of the green numbers, the zero and, where applicable, the double zero, that gives the casino this house edge, and hence the reason roulette is so profitable to the casinos (which becomes apparent when you realize some forms of blackjack have a house edge of lower than 0.5%!).
Of course, while it obviously makes sense to choose European roulette over the American variety whenever possible, if you have no choice and you do play at an American roulette table there is something that is important to note (that is, if you care about winning or losing your hard-earned cash); that is that bets on the first five numbers (one combined bet), i.e. 00, 0, 1, 2, 3, pays out at 6/1 which gives an even higher house edge than all other bets at a nerve-jangling 7.89%. In other words, never, ever place that bet!
Of course, one way of shifting the house edge in your favor is to play with other people’s money. We don’t mean go out stealing, of course, but rather that you take advantage of the many large casino bonuses that are available with online casinos. Doing this can make things between you and the casino just that little more even, and thus your chances of walking away with a bit profit from roulette can be better than ever!