Roulette is a casino game in which players make bets on the outcome of a spin of a wheel. The game emerged in Europe in the 18th century and has since spread to most gambling houses and casinos worldwide. A small ball is released into the spinning wheel and players place bets on which red or black numbered compartment it will enter as it comes to rest. Bets can also be placed on various groups of numbers that pay off at higher odds if the ball lands in them.

A croupier or dealer spins the wheel and a ball is thrown onto it. The wheel has thirty-six colored and numbered compartments (canoes) that alternate between red and black, with the exception of a green zero on European-style wheels and a double-zero on American wheels. The croupier or dealer then announces the number and color of the winning bets, and pays out the bettors according to their betting odds.

Each table carries a placard describing the minimum and maximum bets allowed, including inside and outside bets. Each player places chips on a betting mat in the designated area of the table. A bet placed on six numbers or less is called an Inside bet, and one made on the dozen is an Outside bet. The bets are placed before the croupier starts to spin the wheel.

The house edge of roulette is marginally in favor of the house and depends on the type of wheel, the number of green numbers, the layout of the table, and the bets made by the players. In general, the player should decide on a predetermined budget before entering the game and stick to it. Changing bets mid-round will only increase the house edge.

Whenever possible, players should play on a single-zero roulette wheel rather than an American double-zero one, as the odds of winning are much better. When playing on an American wheel, however, the player should cash out his or her winning bets quickly to avoid losing money. Players should also be careful not to dip into their winnings for future bets, as this will only lead to a loss of more money.