Roulette odds and house edge explained
Every roulette bet on a single zero wheel carries the same 2.70% house edge. Here is where that number comes from and which rules make it better or worse.
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Roulette looks like a game of choices: numbers, colours, columns, splits. In practice, almost every bet on a given wheel carries exactly the same house edge. What changes the odds is the wheel you play on and a couple of table rules. Here is how it works.
The wheel and the zero
A European roulette wheel has 37 pockets: the numbers 1 to 36, half red and half black, plus a single green zero. An American wheel has 38 pockets, adding a double zero.
Every payout in roulette is calculated as if the zero did not exist. A straight up bet on one number pays 35 to 1, which would be a fair price if there were 36 pockets. Because there are 37, the casino keeps a small margin on every spin. That margin is the house edge.
Bets, payouts and probabilities
The table below covers the standard bets on a European single zero wheel. Probabilities are the chance of the bet winning on one spin.
| Bet | Numbers covered | Payout | Chance of winning | House edge |
|---|---|---|---|---|
| Straight up | 1 | 35 to 1 | 1 in 37 (2.70%) | 2.70% |
| Split | 2 | 17 to 1 | 2 in 37 (5.41%) | 2.70% |
| Street | 3 | 11 to 1 | 3 in 37 (8.11%) | 2.70% |
| Corner | 4 | 8 to 1 | 4 in 37 (10.81%) | 2.70% |
| Six line | 6 | 5 to 1 | 6 in 37 (16.22%) | 2.70% |
| Dozen or column | 12 | 2 to 1 | 12 in 37 (32.43%) | 2.70% |
| Red/black, odd/even, 1 to 18/19 to 36 | 18 | 1 to 1 | 18 in 37 (48.65%) | 2.70% |
The edge is the same on every line. Betting on single numbers is higher risk and higher reward than betting on red, but it is not a worse deal in the long run, and betting on red is not a better one.
Where 2.70% comes from: a worked example
Imagine you bet 1 unit on number 17 on each of 37 spins, and every pocket comes up exactly once. You have staked 37 units.
- On 36 spins you lose your 1 unit.
- On one spin you win 35 units and keep your 1 unit stake, so you get 36 units back.
You staked 37 and got back 36. You are 1 unit down, which is 1 in 37, or 2.70% of everything you bet.
The same works for even money. Bet 1 unit on red for those same 37 spins: red wins 18 times (you get 2 units back each time, 36 in total) and loses 19 times. Again you staked 37 and got 36 back.
Real spins do not arrive in neat sets of 37, so short sessions swing widely either way. Over a very large number of spins, results settle close to the 2.70% loss.
Rules that change the odds
American double zero
With 38 pockets and the same payouts, the house edge rises to 2 in 38, which is 5.26%. That is almost double the European figure for the same game. American roulette also has a five number bet (0, 00, 1, 2, 3) paying 6 to 1, which has an even higher edge of 7.89%. If both wheels are available, the single zero wheel is the better choice every time.
La partage and en prison
Some European tables, often labelled French roulette, use a rule for even money bets when the ball lands on zero:
- La partage: you get half your even money stake back.
- En prison: your stake is held for the next spin; if it wins, you get it back without winnings.
Either rule halves the house edge on even money bets, from 2.70% to 1.35%. It does not apply to other bets such as dozens or straight ups, which stay at 2.70%. If you mainly bet red/black, odd/even or high/low, a table with one of these rules is clearly better.
Multiplier and variant tables
Some modern versions add random multipliers on certain numbers. To fund them, the standard straight up payout is often reduced. The overall RTP may be close to the classic game or slightly lower, and it can differ between bet types. Check the rules panel rather than assuming it matches standard roulette.
Common myths
- “Black has come up eight times, so red is due.” This is the gambler’s fallacy. The wheel has no memory. The chance of red on the next spin is 18 in 37 whatever happened before.
- “Hot and cold numbers show a pattern.” Many tables show recent results and statistics. On a fair wheel they are a record of the past, not a guide to the future.
- “Martingale guarantees a profit.” Doubling your bet after each loss produces many small wins and occasional large losses. Each individual bet still carries a 2.70% edge, so the system cannot change the overall result. A run of nine losses in a row on red, which will happen from time to time, means your tenth bet is 512 times your starting stake, and the table maximum may stop you placing it.
- “Covering lots of numbers is safer.” Spreading chips across the layout raises how often you win something, but every chip still carries the same edge. You are simply making many bets at once.
What to check at a licensed casino
- Single or double zero. Look at the wheel and the layout. One green pocket means European rules.
- The rules panel. Check payouts and whether la partage or en prison applies.
- The RTP figure. Most game info screens show it. Standard European roulette should show 97.30%. French roulette with la partage shows 98.65% for even money bets. American roulette shows 94.74%.
- Table limits. Note the minimum and maximum for inside bets (numbers) and outside bets (colours, dozens), which are often set separately.
- Licence. Only play at casinos licensed in your market. See our licensing page for how we confirm licences.
Keep it a game
Roulette is simple and quick, so it is easy to play more spins than you meant to. Set a budget before you start, choose a stake that lets you play the session you want, and stop when the budget is gone. If you notice yourself chasing losses or playing longer than planned, our responsible gambling page has tools and places to get help.