Every bet in roulette comes down to one thing: how many numbers your chip covers. That number determines both the payout and your odds of winning, without exception. What changes between inside bets and outside bets isn’t the expected loss per euro wagered (that’s fixed by whichever variant you’re playing), but how wins and losses are spread across spins. This article covers the exact odds and payouts for each bet type in both European and American roulette, so you know exactly what you’re getting into before you place a chip.
Inside bets vs outside bets in roulette odds payouts and risk all follow directly from one variable: how many numbers a single chip placement covers. Every bet on the layout sits somewhere on a spectrum from one number covered to eighteen, and that coverage figure determines both the payout ratio and the winning probability with no exceptions. What differs across the two categories is not the expected loss per euro wagered (that figure is fixed by the variant), but how wins and losses are distributed across spins. This article covers the exact probability and payout figures for each bet type across both the European and American variants, and how coverage size translates into variance.
The Core Structural Divide Between the Two Bet Categories
The two bet categories in roulette are defined by where a chip sits on the layout and how many numbers that placement covers. Inside bets cover between 1 and 6 numbers. Outside bets cover either 12 or 18 numbers. That coverage range is the single most important variable when reading any roulette wager, because the number of numbers covered directly determines both the payout ratio and the winning probability. Everything else in the game’s math follows from that one fact.
Inside Bet Types, Payouts, and Winning Probabilities
Inside bets are the high-payout, low-frequency end of roulette. They cover between one and six numbers, so the payouts are large but wins are rare. That inverse relationship between coverage and payout holds across every inside bet type and across both single-zero and double-zero variants. Below are the exact payout ratios and winning probabilities for each standard inside bet type in both variants.
Each inside bet type is defined by where the chip sits on the layout, which determines how many numbers it covers. The payout ratio follows directly from dividing 36 by the number of numbers covered and subtracting one. Winning probabilities are slightly lower on the American variant because that wheel has 38 pockets instead of 37, which reduces the chance of landing on any given set of numbers. The five-number bet, which only exists on the American layout, is covered separately below and isn’t included in this table.
| Bet Type | Numbers Covered | Payout Ratio | European Probability | American Probability |
|---|---|---|---|---|
| Straight-up | 1 | 35:1 | 2.70% | 2.63% |
| Split | 2 | 17:1 | 5.41% | 5.26% |
| Street | 3 | 11:1 | 8.11% | 7.89% |
| Corner | 4 | 8:1 | 10.81% | 10.53% |
| Six-line | 6 | 5:1 | 16.22% | 15.79% |
The five-number bet covers pockets 0, 00, 1, 2, and 3. It only exists on the American layout because it requires the double-zero pocket, which isn’t on the European wheel. It pays 6:1. This bet carries a house edge of 7.89%, which is higher than the 5.26% that applies to every other standard wager on the American table. That makes it the worst standard bet on that variant, and the only one whose mathematical profile breaks from the rest of the game.
Because inside bets win rarely but pay large multiples of the stake, a short session will typically look like a long run of losses with the occasional big win mixed in. That’s variance, a direct result of the low coverage and high payout structure. It’s not a sign that the wheel is running cold or hot. Long losing streaks and sudden winning spikes are both normal outcomes of the statistical distribution that inside bets produce.
Outside Bet Types, Payouts, and Winning Probabilities
Outside bets are the higher-frequency, lower-payout end of roulette. They cover either 12 or 18 numbers on a single spin and pay out at either 2:1 or 1:1. Because the coverage is broad, wins come more often, but each win returns a smaller multiple of the stake. The table below shows each outside bet type with its exact coverage, payout ratio, and winning probability for both the single-zero and double-zero variants.
Outside bets split into two groups: even-money bets, which each cover 18 numbers, and dozen and column bets, which each cover 12 numbers. The payout ratio in each group follows from the coverage size. Bets covering 18 numbers pay 1:1, and bets covering 12 numbers pay 2:1, because the standard payout formula divides 36 by the number of numbers covered and subtracts one. Neither group’s winning probability reaches the round number its coverage might suggest. The 18-number bets don’t reach 50%, and the 12-number bets don’t reach 33.33%. That gap exists because the zero pockets aren’t covered by any outside bet, and that’s precisely where the house edge comes from, as covered in the next section.
| Bet Type | Numbers Covered | Payout Ratio | European Probability | American Probability |
|---|---|---|---|---|
| Red / Black | 18 | 1:1 | 48.65% | 47.37% |
| Odd / Even | 18 | 1:1 | 48.65% | 47.37% |
| High / Low | 18 | 1:1 | 48.65% | 47.37% |
| Dozens | 12 | 2:1 | 32.43% | 31.58% |
| Columns | 12 | 2:1 | 32.43% | 31.58% |
Even-money outside bets win at a rate close to, but not equal to, the rate at which they lose. So across a session, you’ll see a steady back-and-forth of small wins and small losses rather than long dry spells broken up by big payouts. Dozen and column bets win roughly one time in three, producing a similar pattern at a slightly lower frequency. Because outside bets cover more numbers, bankroll swings are smaller in either direction over a comparable number of spins than they’d be with inside bets. That said, winning more often on outside bets doesn’t mean you’re in a better mathematical position. The expected loss per unit staked stays at the variant’s standard figure, which is covered in the next section.
The House Edge and Why It Is Identical Across Standard Bets
European roulette has a house edge of 2.70%. American roulette has a house edge of 5.26%. Both figures apply to every standard bet type within their respective variants. A straight-up bet on a single number sits under the same edge as a red/black even-money bet on the same wheel. Choosing between inside and outside bets doesn’t change your mathematical position over the long run. The real difference between the two categories is variance, not expected value.
The European wheel has 37 pockets: numbers 1 through 36 plus a single zero. The American wheel has 38 pockets, adding a double-zero alongside the single zero. Payout ratios across all standard bets are set as though the wheel had only 36 numbers, so the zero pockets represent the gap between a mathematically fair return and what the casino actually pays out. That gap is the house edge. Because the American variant has two zero pockets instead of one, it produces roughly double the edge of the European variant.
Every standard payout ratio comes from the same coverage formula, and zero pockets fall outside the coverage of every standard bet. So the same proportional shortfall from fair value applies no matter which bet you place. On the American variant, a straight-up bet carries an expected loss of about €5.26 per €100 wagered, and that same figure applies to every other standard bet on that wheel. Moving chips from an inside position to an outside position changes how outcomes are distributed across spins, not the long-run mathematical result.
Once expected value is fixed at the variant level, the meaningful difference between any two bets is variance: the size and frequency of swings around the expected outcome. Inside bets sit at the high-variance end, producing infrequent wins of large size. Outside bets sit at the low-variance end, producing more frequent wins of smaller size. A bet’s coverage size directly tells you its variance profile. How many numbers a bet covers is equivalent to how volatile its outcome distribution will be.
How Zero Pockets Affect Outside Bets Specifically
Even-money outside bets cover 18 of the numbered pockets on a European wheel, but the zero pocket sits outside every outside bet’s coverage entirely. The same goes for the double-zero pocket on an American wheel. Because payouts are calculated as though the wheel has only 36 numbers, the zero pockets represent the exact gap between a fair return and the actual return. That gap is most visible on outside bets, where players might expect a near-even proposition but get something measurably worse. The zero result is the specific mechanism by which the house edge is collected on the outside portion of the layout.
Under standard rules, a zero result causes every red/black, odd/even, and high/low bet to lose in full. The same applies to dozen and column bets. That’s why the win probability for an 18-number even-money bet is 48.65% on a European wheel rather than 50%, and why the win probability for a 12-number dozen or column bet is 32.43% rather than 33.33%. The zero pocket accounts for the entire shortfall in both cases. Even-money outside bets are slightly-worse-than-even propositions, not 50/50 wagers. Treating them as 50/50 misrepresents the actual math.
Combining Inside and Outside Bets on the Same Spin
Placing chips on both inside and outside positions during the same spin is allowed under standard roulette rules and is common at the table. Each bet is evaluated independently when the ball settles, so the two categories run in parallel rather than interacting with each other. The result is a mixed outcome profile that reflects both bet types at once. Combining them doesn’t change the expected value of any individual wager. The house edge on each component stays fixed at the variant’s standard figure.
Placing chips across both categories blends the high hit-frequency, low-payout profile of outside bets with the low hit-frequency, high-payout profile of inside bets, producing a middle-variance outcome distribution across the session. This is a variance choice, not an edge-reducing tactic. On a single-zero wheel, each component bet carries a 2.70% house edge, and on a double-zero wheel each carries 5.26%, regardless of what other bets sit alongside it on the layout. A mixed-bet session should be read as a weighted average of the two variance profiles, not as evidence of an improved mathematical position.
Reading Any Roulette Bet as a Coverage-Variance Trade-Off
The difference between the two bet categories comes down to one principle: coverage size determines variance, while the house edge stays fixed at the variant level regardless of where chips sit on the layout. If you can read a bet’s coverage, you can read its full mathematical profile: win frequency, payout ratio, and volatility. What changes across the layout is how outcomes are distributed across spins, not the underlying expected loss per euro wagered.
