When you play in a game of online roulette, you are trying to overcome one factor and one factor primarily, and that would be the house edge. It should be no surprise whatsoever that the casino has a built-in edge in the game of roulette, because that is the way by which it makes money, and could one really begrudge them that?
What exactly IS this house edge
? Well, put very succinctly, it constitutes the difference between what the casino collects from you in a bet and what it pays to you if you happen to win. This is the kind of thing that could commonly be referred to as the "vig" or the "vigorish." I'm sure you've heard that expression more than once as it refers to what a sports bookmaker does. The customer lays 11-to-10 on many sporting events and gets paid at even money. It becomes the losers who are forking out the "vig.".
Please understand that if you were to accept wagers on something that had a 2-to-1 chance of occurring but you only paid off at even money odds when somebody had a winner, you would certainly be sitting pretty, with a rather sizable edge, which is derived from the considerable margin between what you're taking in and what you are paying out. In the long run, that adds up to a lot of profit.
In the online roulette
game, this margin is not nearly as drastic, but don't be under the impression that there won't be a house edge in this game, and that it won't work on every single bet you make. Let's explore what that is, and where it comes from.
It's really kind of simple when you break it down. The probability that any single number winning on an American roulette wheel (i.e., that which there is a zero and double zero) is one in 38. The payout on any "straight bet," which is a bet on a single number, happens to be 35-to-1, which means that you will get back the amount of your original bet in addition to monies equaling 35 times that bet.
The formula that can be used to calculate the house edge is
(Odds Against Winning - House Odds) x Probability of Winning
The odds against winning are 37/1. The house odds (the payoff) are 35/1. That much has already been established. The probability of winning is 1/38. You just have to plug those values into the equation.
When you follow through on the calculations, you get:
(37/1 - 35/1) x 1/38 = 2/38 = .0526315
To express this in terms of a percentage, you move the decimal two places to the right. Rounded down, it comes out to 5.26%. That's the house edge that governs the game of roulette. In fact, with only one exception (where the edge is a little lower), it it is the advantage on every different bet on the table. This 5.26% number represents more of a house advantage than what you'll find most of the time in craps, and it is more than the built-in house edge in blackjack, although we say as a disclaimer that it really depends on how bad a 21 player you are
There is no doubt that there are some things you can do to increase your chances of winning in the short run; to counter the house edge for long enough to have a winning session. And when it comes down to it, the "long run" is really just a succession of short runs. So while you should know what you're up against, you also know that you are not without hope.