The most striking contrast between American and European roulette lies in the number of pockets on the wheel. European roulette boasts 37 pockets, numbered from 0 to 36, while its American counterpart features 38 pockets, including both the standard 0 and an additional 00 pocket.
The main difference between an American and European Roulette wheel is the number of green pockets / zeroes. The European roulette wheel features one green pocket (0) whereas the American Roulette wheel (more popular in Las Vegas) features two of them: 0, 00.