Roulette Odds and House Edge Explained (With Real Numbers)
Roulette odds and house edge are the foundation of every strategy conversation. Before you talk about prediction software, progressions or hot numbers, you need to know what each bet pays, how likely it is to win and how much the casino expects to keep over the long run.
This guide breaks down the maths for European, French and American wheels, explains why accuracy is not the same as profit, and shows where a tool such as RouletteAid can and cannot change the equation.
The three main wheels
- European wheel: 37 pockets (1–36 plus a single zero). Most common online and in Europe.
- French wheel: the same 37 pockets, but with La Partage or En Prison rules on even-money bets, which reduce the house edge on those bets.
- American wheel: 38 pockets (1–36 plus zero and double zero). The extra pocket increases the house edge on most bets.
The payout table is usually the same across wheels, but the probability changes with the number of pockets. That is why the same “35 to 1” straight bet has a different expected value on a European and an American wheel.
Roulette bet payouts and probabilities
| Bet | Numbers covered | Payout | Probability (European) | House edge (European) |
|---|---|---|---|---|
| Straight | 1 | 35 to 1 | 1/37 = 2.70% | 2.70% |
| Split | 2 | 17 to 1 | 2/37 = 5.41% | 2.70% |
| Street | 3 | 11 to 1 | 3/37 = 8.11% | 2.70% |
| Corner | 4 | 8 to 1 | 4/37 = 10.81% | 2.70% |
| Line | 6 | 5 to 1 | 6/37 = 16.22% | 2.70% |
| Column | 12 | 2 to 1 | 12/37 = 32.43% | 2.70% |
| Dozen | 12 | 2 to 1 | 12/37 = 32.43% | 2.70% |
| Red/Black | 18 | 1 to 1 | 18/37 = 48.65% | 2.70% |
| Odd/Even | 18 | 1 to 1 | 18/37 = 48.65% | 2.70% |
| High/Low | 18 | 1 to 1 | 18/37 = 48.65% | 2.70% |
On a European wheel, every standard bet has the same theoretical house edge: 2.70%. The bets differ in variance, not in expected value. A straight bet wins rarely and pays a lot; a red/black bet wins often and pays little. Over a very large number of spins, the casino’s expected share is the same.
American and French variations
On an American wheel, the extra double-zero pocket changes the denominator to 38. Most bets then have a house edge of 5.26%. The five-number bet (0, 00, 1, 2, 3) is even worse for the player, with a house edge of about 7.89%.
On a French wheel with La Partage, an even-money bet returns half the stake when zero hits. That lowers the house edge on red/black, odd/even and high/low to about 1.35%. With En Prison, the stake is held for the next spin instead of being lost immediately, with a similar effect. These rules apply only to the qualifying outside bets; the inside bets keep the standard edge.
The expected-value formula
For a one-unit bet, expected value (EV) is:
EV = (payout × probability of winning) − (1 × probability of losing)
For a European straight bet:
EV = (35 × 1/37) − (1 × 36/37) = 35/37 − 36/37 = −1/37 ≈ −0.027
That is a loss of about 2.7 cents per euro staked, on average, over a long series. The result on any single spin is still random: you can win 35 units or lose one. The house edge is a long-run average, not a prediction for the next spin.
Why accuracy is not the same as profit
Prediction software often reports “accuracy”. That word can mean different things:
- the percentage of spins in which the predicted number was correct;
- the percentage of bets in which the selected figure won;
- the percentage of predictions that matched the software’s own model, even if the player did not bet on them;
- the hit rate of a particular bet type over a short sample.
Those definitions are not interchangeable. A 56.4% average accuracy figure does not automatically mean a 56.4% chance of winning a specific even-money bet, and it certainly does not mean a 56.4% profit. The payout, the stake plan, the table limits and the losing streaks all matter.
For example, a system that wins 56.4% of even-money bets would have a theoretical player edge of about 12.8% before costs: 0.564 × 1 − 0.436 × 1 = 0.128 units per unit staked. That sounds enormous, and it is why accuracy claims need scrutiny. If the same system is betting a progression, the average stake is not one unit, and a single bad streak can wipe out many small wins. If the 56.4% figure is an average across different bet types, it cannot be applied directly to a single bet.
The right question is not “what is the accuracy?” but “what is the expected value after payouts, stake sizing, table limits and fees, and how large is the sample?”
What the RouletteAid test reports
RouletteAid publishes a 5,000-prediction benchmark. The headline figures are:
| Model | Average accuracy |
|---|---|
| Default | 25.4% |
| V7.0 | 48.6% |
| V5.05 + Shield | 53.9% |
| V7.0 + Shield + AI | 56.4% |
The same test reports a +122% total lift over the default model and shows that performance varies by bet type. Outside bets such as red/black and odd/even have higher absolute accuracy; inside bets such as straight numbers have lower absolute accuracy but much larger payouts when they hit. The test chart reports the largest relative improvement on straight bets.
This is a developer-run benchmark, not an independent audit. It is useful as product evidence, but it is not a guarantee. The test does not tell you the full stake plan, the table limits or the variance you will experience in a live session.
See the full 5,000-prediction chart on the RouletteAid shop page.
How prediction software tries to shift the equation
A prediction tool can try to improve results in three ways:
- Bet selection. Instead of betting randomly, it selects the figure with the strongest measured hit rate or the most plausible physical pattern.
- Stake management. It applies a progression that is intended to match the volatility of the selected figure.
- Risk control. It pauses or stops when the measured hit rate deteriorates, which is the idea behind RouletteAid’s Shield.
None of those changes the underlying wheel. They change how you choose and size your bets. If the selection has a genuine edge, better sizing can preserve it. If the selection has no edge, no progression can turn a negative expected value into a positive one over the long run. That is why the test data and the methodology matter more than the size of the promised win rate.
Bankroll, variance and table limits
Two players can use the same bet selection and get very different results because of variance and bankroll. A progression that requires a large bankroll can fail at a table with a low maximum bet. A conservative plan may survive longer but win less per hour.
Before using any software, decide:
- the total amount you are willing to lose;
- the maximum stake per spin;
- the table minimum and maximum;
- the number of losing steps your progression can survive;
- the stop-loss and take-profit levels.
RouletteAid’s Shield is a risk-control layer, not a magic shield. It pauses a progression when the measured hit rate falls below a threshold and resumes after two new results. It can help you avoid chasing a cold figure, but it cannot make a bad bet good.
Frequently asked questions
Which roulette bet has the best odds?
On a European wheel, all standard bets have the same theoretical house edge of 2.70%. The difference is variance and payout, not expected value. French even-money bets with La Partage can reduce the edge to about 1.35%.
Is red/black safer than a straight number?
It wins more often, but it pays less. The house edge is the same on a European wheel. “Safer” is about variance, not expected value.
Can prediction software change the house edge?
It can try to select bets with a better measured hit rate, but it cannot change the wheel. Any claimed edge must be demonstrated with a large, transparent sample and must survive real table limits and variance.
Does a 56.4% accuracy figure mean a 56.4% profit?
No. Accuracy, payout and stake size are different things. A 56.4% hit rate on an even-money bet implies a theoretical edge before costs, but the same number cannot be applied to every bet type or progression. Treat the figure as test evidence, not a profit guarantee.
Where can I see the full test chart?
The chart is on the RouletteAid shop page and discussed in our RouletteAid AI review.
Sources and further reading
- Roulette: wheel types, bets and payouts — Wikipedia.
- BeGambleAware — support and advice for safer gambling.
- UK Gambling Commission — regulatory information.
Responsible gambling
RouletteAid is entertainment and decision-support software, not a guaranteed win system. Gambling involves risk and is 18+. Set limits, never chase losses and stop if gambling stops being fun. If you need support, contact BeGambleAware or Gambling Therapy.
Disclosure: This guide is published by RouletteAid and links to our software. The benchmark figures are from RouletteAid’s published 5,000-prediction test and are not a promise of future results.
More roulette guides: Browse all RouletteAid guides.