The first version of Roulette was the European one. It has a big spinning wheel with numbers from 0 to 36, and the players guess either the numbers or the colors where they think a small white ball is going to land. It’s very simple, but that doesn’t make it easy to beat.
The European Wheel (or the French Wheel, since it was first created in France) became popular very quickly. That lead to the news about the new game crossing the ocean all the way to America, and Vegas being very interested in it. The European version has 37 slots – the 1-36 numbers and 0. The layout is random and not symmetrical. The rules changed when the game arrived to America, because the casino owners didn’t like the fact that the original version favors the players over the house.
The American Roulette has 38 slots – the 1-36 numbers, 0 and 00. Thanks to the extra 00, the odds changed in favor of the casinos. In addition to that, the randomness of the layout is gone – the numbers are instead placed in pairs across from each other. The American version resulted in players having much less luck than in Europe, so it was more beneficial to the casino owners and they decided to keep it. It seems like a very little change – just one extra number – but that’s not the truth when you look at the odds:
On the American Wheel on a single bet of one number the casino edge is 2/38, which is 5.26%.
A single bet of one number on the European Wheel has a casino edge of 1/37, which is 2.70%. That makes a very big difference.
The conclusion is that as a player it’s more beneficial to choose the European version, whether you play online or in a real casino.