Roulette is one of the world’s most iconic casino games—simple to learn, exciting to play, and instantly accessible for beginners.
Yet, while luck drives every spin, understanding a few key principles can give you a sharper edge. Before diving into online casinos, take time to learn the essentials that shape every roulette strategy: the house edge, betting odds, and payout structures.
In this guide, you’ll explore the main types of bets, how odds vary across roulette variations, and why mastering basic roulette statistics can greatly enhance your playing experience.
Roulette Strategy Fundamentals
Most players know the basics of roulette and may even have tried some traditional bets. The key difference lies in the wheel itself: European roulette has 37 pockets numbered 1–36 plus a single zero, while American roulette adds a double zero, increasing the total to 38 pockets.
At the start of each round, the croupier spins the wheel and releases a small metal ball. When the ball comes to rest in a pocket, the outcome determines whether your bet wins or loses. All wagers must be placed before the wheel stops spinning.
Common bets—such as red/black, odd/even, or straight-up single numbers—are instantly recognizable. But roulette also offers a variety of more complex betting options. Knowing the odds behind these bets is essential to making informed decisions. This guide will walk you through the main bet types and their corresponding odds.
Roulette Probability Explained
Like all forms of gambling, roulette involves real financial risk. Understanding roulette odds and statistics before placing bets can help you make smarter decisions. The best starting point is probability.
Probability is the measure of how likely an event is to occur. It is usually expressed as a fraction or a percentage. For instance, a 4/5 chance is the same as an 80% probability. A simple way to visualize this is on a scale from 0 to 1: events near 0 are unlikely, those near 1 are very likely, and 0.5 represents a 50/50 chance.
In roulette, probability applies to every spin of the wheel. A European wheel has 37 possible outcomes, while an American wheel has 38. Each spin is random and independent, with only two results for any given bet—you either win or lose.
To calculate probability, divide the number of winning outcomes by the total number of possible outcomes. This principle underpins all roulette odds, and the next sections of this guide explain how it applies to specific bets.
Understanding Roulette Odds
With a clear grasp of probability and the basic method for calculating chances, you can now apply this knowledge to roulette odds. The general formula is:
Odds of winning = Probability of winning ÷ (1 – Probability of winning)
In simpler terms, it comes down to comparing the number of ways to win with the number of ways to lose. While this may sound complex, examples make it much easier to understand.
Example 1: Coin Toss
A coin toss has two possible outcomes: heads or tails. The probability of winning is 1 way to win ÷ (1 win + 1 loss) = 0.50. Expressed as a percentage, that’s 50%. This basic example mirrors the 50/50 bets found in roulette, such as red/black or odd/even.
Example 2: Roulette Bet on Four Numbers
In European roulette, there are 36 winning numbers. If you bet on 4 numbers, you calculate 36 ÷ 4 = 9. Subtract 1, leaving 8, which means the odds are 8:1. A £100 winning bet would return £800 in winnings.
These calculations show how probability translates into real-world roulette odds, helping you see the risk-to-reward balance in every wager.
Essential Roulette Odds
If the roulette odds formula feels overwhelming, try working through a few examples on paper. Once you practice applying it, the process becomes easier and helps you understand how to build a betting strategy. Remember that odds vary depending on which version of roulette you play.
European Roulette Odds
European roulette features 37 pockets: numbers 1–36 (18 red, 18 black) plus a single green zero. A single-number bet pays 35:1. For example, a £10 stake would return £350 in winnings plus your original £10 stake, totalling £360.
American Roulette Odds
American roulette adds a double zero (00), making 38 pockets. This extra slot increases the house edge, meaning your chances of winning are slightly lower than in European roulette. If the ball lands on 0 or 00 and you didn’t bet on those numbers, your wager is lost.
Outside Bets
Outside bets cover large sections of the board and give players higher chances of winning, though with smaller payouts. Common outside bets include:
- Red/Black – Even-money bet (1:1). You win if the ball lands on your chosen colour.
- Odd/Even – Another 1:1 bet, based on predicting whether the winning number is odd or even.
- Low/High – Pays 1:1 if the ball lands on 1–18 (low) or 19–36 (high).
- Column – Covers one of three vertical columns (12 numbers each). Pays 2:1.
- Dozens – Predicts whether the ball lands in 1–12, 13–24, or 25–36. Pays 2:1.
Outside Bet Odds Table:
| Roulette Bet | Payout | European Odds | American Odds |
|---|---|---|---|
| Red/Black | 1:1 | 48.65% | 47.37% |
| Odd/Even | 1:1 | 48.65% | 47.37% |
| High/Low | 1:1 | 48.65% | 47.37% |
| Column | 2:1 | 32.4% | 31.6% |
| Dozens | 2:1 | 32.4% | 31.6% |
Inside Bets
Inside bets focus on smaller groups of numbers, offering bigger payouts but lower chances of winning.
- Single Number (Straight Up) – Bet on one number, payout 35:1. Highest risk, highest reward.
- Split – Bet on two adjacent numbers, payout 17:1.
- Street – Covers three numbers in a row, payout 11:1.
- Corner – Covers four numbers that meet at one corner, payout 8:1.
- Basket (American only) – Covers 0, 00, 1, 2, and 3. Pays 6:1.
- Double Street – Covers two rows of three numbers (six total). Pays 5:1.
The House Edge in Roulette
The house edge is the built-in advantage that ensures casinos make a profit, both online and in land-based venues. While it may appear small, over thousands of spins it adds up to a significant margin. Even in a single session, the house edge steadily reduces your bankroll over time.
House Edge in European Roulette
On a European roulette wheel, a straight-up bet has a 1/37 chance of winning, since there are 37 possible numbers but only one winning outcome. For example, if you place £1 on each number, you will always win on one of them—but the payout is £36 while your total stake is £37.
This simple experiment shows the house edge in action: for every £37 wagered, you get £36 back, meaning £1 goes to the casino. Over the long run, this translates into a 2.7% house edge (£1 out of every £37 wagered).
While short-term play may deliver wins or losses outside this ratio, over thousands of spins the house edge holds steady, ensuring the casino’s built-in advantage.
House Edge in American Roulette
In American roulette, the addition of the double zero (00) increases the casino’s advantage without changing the payout structure. This means players face the same payouts as in European roulette but with worse odds.
For a straight-up single number bet, the probabilities are:
- European roulette: 1/37
- American roulette: 2/38
That extra pocket nearly doubles the casino’s long-term profit margin, resulting in a 5.26% house edge for American roulette.
Summary: Improving Your Odds in Roulette
If you enjoy excitement and the feel of a classic casino, online roulette is an excellent choice. You don’t need advanced math skills to play, but understanding roulette odds is key to separating strong strategies from weak ones.
As outlined, roulette bets vary in both risk and reward, and the odds shift depending on which variant you choose. Most online versions are based on either European (or French) roulette or American roulette.
When picking a game, review the odds for each variant before betting. Inside bets offer bigger payouts but lower chances of success, while outside bets provide better winning probabilities with smaller but more frequent returns.
Ultimately, American roulette can be entertaining, but its higher house edge makes it less favorable. If you want the best long-term value, stick with European roulette, where the odds work more in your favor.
