These are terms that you’ll hear often in roulette discussions so it’s a good idea to take the time and understand what these terms mean, the differences between the games and the odds on each variation of roulette. Roulette has changed very little over the past few centuries. Historians have dated both ‘double zero’ and ‘single zero’ roulette back to the late 1700’s and although the popularity of the game has spread worldwide and ebbed and flowed the 18th-century player would have no problem recognizing today’s version of the game.

The terms ‘American Roulette’ and ‘European Roulette’ simply refer to the number of zeros on the wheel. This is significant since this is where the ‘house’ gains its primary mathematical advantage. The roulette wheel has 36 numbered spots and either one zero for a total of 37 spots or a zero and a ‘double zero’ for a total of 38 spots. The house edge in single zero roulette is 2.7% while the house edge in ‘double zero’ roulette is 5.26%.


One of the easiest ways to understand the house edge–as well as the concept of getting ‘fair odds’ on a bet–can be seen in roulette single number bets. Assume for a moment that you came across a ‘no zero’ roulette wheel at a casino in some alternate dimension. You sit down to place a bet on one of the 36 numbers on the wheel. You don’t have to be a math genius to understand that your odds of hitting a specific number is 1 in 36, right? But here’s the problem–a single number bet in roulette pays 35 to 1. Since your chances of hitting a number is 1 in 36 a payout that reflected the ‘true odds’ would be 36 to 1. That means the casino is getting the best of it on every spin. It might go unnoticed to a player since 35 to 1 is a nice score but you simply can’t turn a profit in the long run getting paid at less than ‘true odds’. But don’t forget that this is a ‘no zero’ wheel. The addition of the single zero (European Roulette) makes the chances of hitting any one number 37 to 1. The addition of the double zero (American Roulette) makes the chances of hitting any one number 38 to 1. The ‘true odds’ on the different variations would change accordingly but they don’t–they’re 35 to 1 in every instance.

You’ll hear talk of ‘true odds’ throughout gambling and particularly among ‘sharp’ players. It’s especially common in poker, sports betting and horse racing. Here’s a couple of other good terms to know. Any bet that pays less than true odds–such as the individual number bet in roulette–is an underlay. Any bet that pays more than true odds is an overlay.

Back to roulette for a moment–here’s another important thing to keep in mind on both American and European roulette. Every bet on the board pays off at less than true odds. This is even true for the most basic of bets: red or black. The odds of hitting ‘red’ or ‘black’ is 1.05 to 1 on an American roulette wheel and 1.01 to 1 on a European roulette wheel. No matter how many bets you string across the board and no matter how many complex combinations you use that won’t change the house edge. The house edge remains the same on any bet or any combination of bets: 2.7% for European (single zero) roulette or 5.26% for American (double zero) roulette.