What is the house edge in roulette?

First of all, it is important to note that the American Roulette and the European Roulette have different house edges, since the first one has an extra zero house. So, the base house edge on American Roulette wheels (double zero) is 5.26% and the base house edge on European Roulette wheels (single zero) is 2.70%. In terms of money, this means that a roulette player on the American roulette can lose 5.26 units for every 100 units wagered, while the player on the European roulette may lose 2.7 units per 100 units wagered.