Roulette Odds
Roulette odds represent your probability of winning on any given spin. Understanding the difference between true mathematical odds and casino payout odds is essential for informed play. This page explains how roulette odds work, why they differ from payouts, and how the house edge is built into every bet.
What Are Roulette Odds?
Roulette odds express the likelihood of a specific outcome occurring. They are determined by the number of ways to win divided by the number of ways to lose.
For example, betting on a single number in European roulette means 1 way to win and 36 ways to lose, giving true odds of 36:1. In probability terms, this is a 2.70% chance of winning (1 out of 37 total outcomes).
Odds can be expressed as:
- Ratio format: 36:1 (ways to lose : ways to win)
- Probability format: 2.70% (chance of occurrence)
- Decimal format: 1/37 = 0.027
True Odds vs Casino Payout Odds
True odds reflect the actual mathematical probability of winning. Payout odds are what the casino pays when you win. These two figures are not the same, and the difference creates the house edge.
True odds for a straight up bet in European roulette: 36:1
Payout odds: 35:1
The casino pays one unit less than the true odds. If you bet $10 and win, the fair payout would be $360 (true odds), but the casino pays only $350 (payout odds). This one-unit shortfall applies across all bet types and is how casinos generate profit.
Another example:
- Red/Black true odds in European roulette: 19:18 (19 ways to lose, 18 ways to win)
- Red/Black payout odds: 1:1
The true probability of winning a red/black bet is 18/37 = 48.65%. A fair payout would reflect these odds, but the casino pays even money instead.
The House Edge in Roulette
The house edge is the mathematical advantage the casino holds over players, expressed as a percentage of total wagers. It is created by the gap between true odds and payout odds.
European roulette house edge: 2.70%
American roulette house edge: 5.26%
The house edge means that over time, for every $100 wagered, a player can expect to lose $2.70 on a European wheel or $5.26 on an American wheel. This is a long-term statistical average and does not predict short-term outcomes.
The house edge is the same for all standard roulette bets on a given wheel type. Whether you bet on a single number, red/black, or a dozen, the casino's advantage remains constant.
Odds for Inside Bets
| Bet Type | True Odds (EU) | Payout Odds | Probability (EU) | Probability (US) |
|---|---|---|---|---|
| Straight Up | 36:1 | 35:1 | 2.70% | 2.63% |
| Split | 17.5:1 | 17:1 | 5.41% | 5.26% |
| Street | 11.33:1 | 11:1 | 8.11% | 7.89% |
| Corner | 8.25:1 | 8:1 | 10.81% | 10.53% |
| Six Line | 5.17:1 | 5:1 | 16.22% | 15.79% |
For detailed descriptions of each bet type, see the guide to inside bets in roulette.
Odds for Outside Bets
| Bet Type | True Odds (EU) | Payout Odds | Probability (EU) | Probability (US) |
|---|---|---|---|---|
| Red / Black | 1.06:1 | 1:1 | 48.65% | 47.37% |
| Even / Odd | 1.06:1 | 1:1 | 48.65% | 47.37% |
| High / Low | 1.06:1 | 1:1 | 48.65% | 47.37% |
| Dozens | 2.08:1 | 2:1 | 32.43% | 31.58% |
| Columns | 2.08:1 | 2:1 | 32.43% | 31.58% |
For detailed descriptions of each bet type, see the guide to outside bets in roulette.
European vs American Roulette Odds
The key difference between European and American roulette is the number of pockets on the wheel.
European roulette: 37 pockets (numbers 1-36 plus a single zero)
American roulette: 38 pockets (numbers 1-36 plus both a single zero and a double zero)
The extra pocket in American roulette reduces the probability of winning on every bet type. For example:
- Straight up probability (EU): 1/37 = 2.70%
- Straight up probability (US): 1/38 = 2.63%
While the difference may seem small on a single spin, it doubles the house edge from 2.70% to 5.26%, significantly increasing expected losses over time.
For a complete comparison, see American vs European roulette.
Probability Table for All Roulette Bets
| Bet Type | Numbers Covered | EU Probability | US Probability |
|---|---|---|---|
| Straight Up | 1 | 2.70% | 2.63% |
| Split | 2 | 5.41% | 5.26% |
| Street | 3 | 8.11% | 7.89% |
| Corner | 4 | 10.81% | 10.53% |
| Six Line | 6 | 16.22% | 15.79% |
| Red / Black | 18 | 48.65% | 47.37% |
| Even / Odd | 18 | 48.65% | 47.37% |
| High / Low | 18 | 48.65% | 47.37% |
| Dozens | 12 | 32.43% | 31.58% |
| Columns | 12 | 32.43% | 31.58% |
Expected Value in Roulette
Expected value (EV) is the average amount a player can expect to win or lose per bet over the long term. In roulette, all standard bets have a negative expected value due to the house edge.
Expected value formula:
EV = (Probability of Win × Payout) - (Probability of Loss × Stake)
Example: $10 bet on red in European roulette
- Probability of win: 18/37 = 48.65%
- Probability of loss: 19/37 = 51.35%
- Payout if win: $10
- EV = (0.4865 × $10) - (0.5135 × $10) = -$0.27
The expected value is -$0.27, meaning you can expect to lose 27 cents for every $10 wagered on red over time. This equals the 2.70% house edge.
Why All Roulette Bets Have the Same House Edge
All standard roulette bets carry the same house edge because the payout structure is designed to maintain a consistent advantage for the casino.
Whether you bet on a single number, a dozen, or red/black, the casino pays less than the true odds by the same proportional amount. This creates a uniform 2.70% edge on a European wheel and 5.26% edge on an American wheel across all bet types.
Some players believe that certain bets offer better value, but mathematically, all standard roulette bets are equivalent in terms of expected loss.
Common Misunderstandings About Roulette Odds
Believing past results influence future spins. Roulette outcomes are independent. The ball has no memory. If red hits ten times in a row, the probability of red on the next spin is still 48.65% on a European wheel.
Thinking betting systems change the odds. No progression system, pattern betting, or staking strategy alters the house edge or improves your long-term expectation. Each bet carries the same mathematical disadvantage.
Confusing probability with payout. A 2.70% chance of winning does not mean a 2.70% payout. Probability and payout are different concepts. Higher payouts compensate for lower probabilities.
Assuming odds improve with larger bets. Bet size does not affect probability or house edge. A $1 bet and a $1,000 bet on the same outcome have identical odds.
How to Use Odds to Understand Risk
Understanding roulette odds helps you evaluate risk and make informed decisions about bet selection and bankroll management.
Bets with higher probabilities (like red/black at 48.65%) win more frequently but pay less. Bets with lower probabilities (like straight up at 2.70%) win rarely but pay significantly more.
Neither bet type is inherently better. The choice depends on your risk tolerance and session goals. Conservative players may prefer frequent small wins, while risk-tolerant players may chase larger payouts despite lower hit rates.
Use the roulette payout calculator to see exact probabilities and payouts for different bet types and stake amounts.