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Roulette Calculator
Calculate roulette odds, payouts, probability, and house edge for every bet type. Covers European, American, and French roulette variants.
Roulette odds calculator quick answer
A roulette odds calculator compares the number of winning wheel pockets with the posted payout. European roulette has 37 pockets, American roulette has 38, and French roulette uses 37 with La Partage on even-money bets. The extra zero pocket is why every standard roulette bet has negative expected value.
- A straight-up European roulette number wins 1 in 37 spins, or 2.70%, and pays 35:1.
- A $10 even-money bet loses about $0.27 per spin on European roulette and about $0.53 on American roulette.
- French La Partage cuts the house edge on red/black, odd/even, and high/low bets to 1.35%.
- Multiple roulette bets add coverage and variance, but they do not remove the house edge.
Roulette odds are simple once you separate payout from probability
Roulette looks messy because the table has many named bets, but the math is plain. Count the pockets you cover, divide by the number of pockets on the wheel, then compare that probability with the payout. A straight-up number covers one pocket. Red covers eighteen pockets. A dozen covers twelve. The zero pockets are where the casino margin lives.
The payout side is where many players get tripped up. A straight-up number pays 35:1, which sounds fair until you notice a European wheel has 37 pockets. Fair payout would be 36:1. American roulette is worse because the wheel has 38 pockets, but the table still pays the same 35:1. The calculator makes that gap visible as expected value instead of burying it in casino language.
If you only remember one rule, remember this: choose French roulette first, European roulette second, and American roulette last. French roulette with La Partage gives half your stake back on even-money bets when zero hits, which cuts those bets to a 1.35% house edge. European roulette sits at 2.70%. American roulette sits at 5.26%, and its five-number bet is worse at 7.89%.
Multiple bets can still be useful if you are planning a session budget. Covering more numbers raises the chance that something wins on a given spin, but the total stake also rises. A player spreading $30 across three dozen bets has not beaten roulette. They have bought broad coverage at the same negative expectation. The calculator is useful because it keeps stake size and expected loss visible while you experiment.
Betting systems deserve less respect than they get. Doubling after losses, increasing after wins, or cycling through Fibonacci steps changes the shape of the ride. It does not change the wheel. Table limits and bankroll limits eventually punish systems that depend on infinite money and infinite allowed bet size. Use the cost-of-playing section as the honest version of a system test: what does this stake usually cost over time?
For online roulette, the best use of this page is not to "find a winning bet." It is to avoid the worst game and set a sane limit before playing. If a casino gives you a choice between single-zero and double-zero roulette, the calculator shows why the single-zero table is the better seat. If a bonus extends your bankroll, treat that as more trial spins, not as a way to erase the house edge.
Roulette payout and probability examples
These common roulette bets show why the posted payout is not the same as the true chance of winning. Use the calculator above to change stake size and wheel variant.
| Bet | Pockets covered | European probability | American probability | Payout |
|---|---|---|---|---|
| Straight-up number | 1 | 2.70% | 2.63% | 35:1 |
| Split | 2 | 5.41% | 5.26% | 17:1 |
| Street | 3 | 8.11% | 7.89% | 11:1 |
| Corner | 4 | 10.81% | 10.53% | 8:1 |
| Six line | 6 | 16.22% | 15.79% | 5:1 |
| Dozen or column | 12 | 32.43% | 31.58% | 2:1 |
| Red/black | 18 | 48.65% | 47.37% | 1:1 |
Roulette variant house-edge comparison
The fastest roulette decision is choosing the wheel. Single-zero and La Partage rules matter more than any betting system.
| Variant | Wheel pockets | Best standard bet | House edge | Practical read |
|---|---|---|---|---|
| French roulette | 37 | Even-money bets with La Partage | 1.35% | Best common roulette rule set when available. |
| European roulette | 37 | Any standard bet except special rules | 2.70% | The default version to prefer over American roulette. |
| American roulette | 38 | Most standard bets | 5.26% | The 00 pocket nearly doubles the cost of play. |
| American five-number bet | 38 | 0, 00, 1, 2, 3 | 7.89% | The worst standard roulette bet. Avoid it. |
Roulette Calc questions
How do you calculate roulette odds?
Roulette odds are winning pockets divided by total pockets. A straight-up European roulette bet covers 1 pocket out of 37, so its win probability is 1/37, or 2.70%. American roulette uses 38 pockets because it has 0 and 00.
How do you calculate roulette payout?
Roulette payout is stake multiplied by the posted payout ratio. A $10 straight-up bet at 35:1 returns $350 profit plus the original $10 stake if it wins. The calculator separates profit, probability, house edge, and expected value.
Can multiple roulette bets improve your odds?
Multiple roulette bets can cover more pockets, so they can increase the chance of hitting something on a spin. They also increase the total amount at risk. The combined expected value still follows the same house edge for the wheel and bet mix.
Is European roulette better than American roulette?
European roulette is better for players because it has one zero instead of two. The standard house edge is 2.70% on European roulette and 5.26% on American roulette. French roulette is better again on even-money bets when La Partage is active.
Do roulette betting systems change the house edge?
No. Martingale, Fibonacci, D'Alembert, and similar roulette systems change bet sizing and session variance, but they do not change wheel probability or payout ratios. A negative expected value game stays negative.
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