Outside Bets

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Written by Ian Mac
Ian Mac
Ian Mac is a dedicated content writer and editor with consistent 5-star feedback when it comes to creating high-quality gambling content. He writes about casino bonuses, casino destinations and casino games including slots, roulette and blackjack.
, | Updated: September 26, 2025

Roulette is a classic table game offered at most casinos. The game’s popularity has only grown since online casinos entered the gambling scene. Nowadays, roulette is more accessible than ever. Countless articles – and even books – are devoted to examining the game.

One of the main reasons so many casino fans enjoy this table game is its simplicity. Unlike blackjack or poker, roulette does not require any special knowledge. In addition, it is an action-packed game that keeps players engaged.

The primary objective in roulette is to predict which number will come up on the current spin. Roulette relies entirely on chance, meaning you cannot use a strategy to make an accurate prediction. The game offers a wide range of betting options. Roulette bets fall into two categories – inside and outside bets.


Introduction to Outside Bets

1Outside Bets

Outside bets are placed in the boxes located outside the number grid. Each outside betting area is clearly labeled. All types of outside bets have one thing in common – they cover a broad range of numbers, either 12 or 18. Because they are low-risk wagers, the probability of winning is high, but the payout is low.

2Odds of Outside Bets

Odds express the ratio between all possible ways to win and all possible ways to lose. As already mentioned, outside bets cover either 12 or 18 numbers, depending on the wager you choose. If you play a single-zero roulette variant, the wheel contains 37 pockets.

Suppose you place an outside bet that covers 12 numbers. In that case, you have 12 ways to win and 25 ways to lose. Therefore, the true odds of winning an outside bet covering 12 numbers are 12/25. If you play double-zero roulette, the wheel has 38 pockets, which reduces the odds of success to 12/26.

You can use the same approach to calculate the odds of winning outside bets that cover 18 numbers. On a single-zero roulette table, the odds of winning an outside bet are 18/19. If you play on a double-zero wheel, the odds of success become 18/20.

3Probabilities of Outside Bets

Probabilities compare the possible ways to win with all possible outcomes. If you play single-zero roulette and place an outside bet that covers 12 numbers, the probability of winning is 12/37 = 0.3243. Multiply this decimal by 100 to convert it to a percentage – 0.3243 x 100 = 32.43%. If you play double-zero roulette, the probability of winning an outside bet that covers 12 numbers is 12/38 = 0.3158 x 100 = 31.58%.

If you play single-zero roulette and place an outside bet that covers 18 numbers, the probability of success is 18/37 = 0.4865 x 100 = 48.65%. Conversely, on a double-zero wheel, the probability of winning an outside bet that includes 18 numbers is 18/38 = 0.4738 x 100 = 47.38%. Refer to the table below for a summary of this information.

Bet Single-Zero Roulette Probability Double-Zero Roulette Probability
Outside bets that cover 12 numbers (Columns and Dozens) 32.43% 31.58%
Outside bets that cover 18 numbers (Red/Black, Odd/Even, and High/Low) 48.65% 47.38%


Different Types of Outside Bets

Column Bets
blank Dozen Bets
blank Bets on Color
blank Bets on Odd/Even
blank Bets on High/Low

Column Bets

A roulette layout consists of three columns of 12 numbers each. Winning column bets are paid at odds of 2:1. The numbers covered by the three different columns are as follows:

  • 1st column: 1, 4, 7, 10, 13, 16, 19, 22, 25, 28, 31, 34
  • 2nd column: 2, 5, 8, 11, 14, 17, 20, 23, 26, 29, 32, 35
  • 3rd column: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36

Please note that the zero pocket(s) is/are not included in any of the columns. Players place their chips in one of the boxes labeled “2 to 1,” located at the bottom of the chosen column. If we ignore the zero pocket(s) for a moment, a column bet covers exactly one third of the wheel. On the French table, this bet is known as Colonne.

Dozen Bets

The roulette layout features three dozens, each containing 12 numbers. The first dozen covers numbers 1 through 12, the second spans 13 through 24, and the last includes 25 through 36. The payout is 2:1, and, like the column bet, this wager excludes the zero pocket(s).

You may have already noticed that the dozen bet is very similar to the column bet. The only distinction between them is the set of numbers they cover. To place a dozen bet, position your chips in one of the boxes marked as “1st 12” (P12 in French Roulette), “2nd 12” (M12), or “3rd 12” (D12).

Bets on Color

Betting on the color of the winning number is extremely popular among roulette fans. A roulette wheel contains pockets that alternate between black and red. Only the zero pocket(s) is/are colored green. A red/black bet allows players to cover all red or all black numbers. There are 18 red pockets and 18 black pockets. If the ball lands in a zero pocket, all red and black bets lose.

To place a color bet, position your chips in one of the boxes labeled “Red” or “Black”. These boxes are located beneath the “2nd 12” betting box. In French Roulette, the wager is called Rouge (red) ou Noir (black). Chips are placed in the box illustrating a diamond colored red and black. The payout for this bet is 1:1.

Bets on Odd/Even

No matter whether you play a single-zero or double-zero version of roulette, the wheel contains 18 odd (e.g., 1, 3, 5, 7, etc.) and 18 even (e.g., 2, 4, 6, 8, etc.) numbers. The payout is 1:1 because both bets – odd and even – offer equal chances of winning. Remember, the number zero is neither even nor odd.

To bet on odd numbers, place your chips on the betting area to the right of the “Black” betting box (below the “3rd 12” box). If you think the winning number will be even, place your chips in the box to the left of the “Red” betting box (below the “1st 12” box). Players who prefer French Roulette should know that this bet is called Pair (even) ou Impair (odd).

Bets on High/Low

The numbers on the roulette wheel are divided into low (1–18) and high (19–36). This bet does not include the zero pocket(s). As you may have noticed, each group contains 18 numbers in total. To place a High/Low bet, put your chips in the boxes labeled as “1 – 18” or “19 – 36”. On the French table, this wager is known as Passe (high numbers) or Manque (low numbers). High/Low bets pay 1:1.


Even-Money Bets Explained

In roulette, even-money bets are wagers that pay 1:1, including Red/Black, High/Low, and Odd/Even. These bets give players the chance to win an amount equal to their original stake. Although even-money bets offer almost equal chances of winning or losing, many newcomers assume they provide a full 50% chance. They often overlook the effect of the zero pocket(s).

Recognizing which bets are even-money is important, because the European and French versions of the game feature two special rules – “La Partage” and “En Prison”. These rules apply only to even-money bets and reduce the house edge from 2.70% to 1.35% when the ball lands on zero.

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