Odd or even is an outside roulette bet that wins if the ball lands on any odd number or any even number from 1 to 36. It pays 1 to 1. It is not a true 50/50 bet because zero, and double zero on American wheels, make both sides lose.
Quick Facts
- Odd covers 18 numbers: 1, 3, 5, up to 35.
- Even covers 18 numbers: 2, 4, 6, up to 36.
- Zero is neither odd nor even for betting settlement.
- Standard payout is 1 to 1.
- European win probability: 18/37 = 48.65%.
- American win probability: 18/38 = 47.37%.
- The house edge is 2.70% on European roulette and 5.26% on American roulette.
Plain Talk
Odd or even is one of the cleanest-looking bets on the roulette layout. You do not pick a number. You pick a category. If the winning number belongs to that category, you win even money.
That simplicity is why many players treat it like a coin toss. It is close to a coin toss, but not equal to one. A coin has two sides. A European roulette wheel has 37 pockets. Odd covers 18. Even covers 18. The extra pocket is zero, and zero does not help either side.
On an American wheel, the situation is worse. Odd still covers 18 numbers. Even still covers 18 numbers. But the wheel has 38 pockets because it includes both 0 and 00. Two pockets now kill the bet instead of one.
This page is about the odd/even bet only. For a wider comparison of all outside wagers, read inside vs outside bets. For the full probability table, use roulette odds or the roulette odds calculator.
How It Works
The odd/even bet is settled after the ball lands and the dealer marks the winning number with the dolly.
| Bet | Covered numbers | Does zero win? | Payout |
|---|---|---|---|
| Odd | 18 | No | 1 to 1 |
| Even | 18 | No | 1 to 1 |
| European zero | 0 | No for odd/even | Losing result |
| American double zero | 00 | No for odd/even | Losing result |
Odd and even are official outside bets on regulated layouts. Public rules from the Nevada roulette rules of play and the Massachusetts roulette rules show how roulette wagers are placed and settled on the layout. The payout and house-edge structure is also summarized by the Wizard of Odds roulette basics.
Odd/even probability by wheel
| Wheel type | Winning pockets | Losing pockets | Total pockets | Win probability | House edge |
|---|---|---|---|---|---|
| European | 18 | 19 | 37 | 48.65% | 2.70% |
| American | 18 | 20 | 38 | 47.37% | 5.26% |
| French with La Partage | 18 | 18.5 effective on zero | 37 | 48.65% | 1.35% on even-money bets |
French roulette needs a note. With La Partage or En Prison, even-money bets may get special treatment when zero lands. That can reduce the effective house edge to about 1.35% on qualifying even-money bets. It does not make the bet positive expectation.
Roulette Table Example
A player buys in for 200 units and bets 20 units on odd at a European single-zero table.
| Spin result | Settlement | Bankroll effect |
|---|---|---|
| 17 lands | Odd wins | +20 units profit |
| 24 lands | Odd loses | -20 units |
| 0 lands | Odd loses under normal rules | -20 units |
| 0 lands with La Partage | Half the stake is returned | -10 units |
The player may feel that odd and even are safer because the bet wins often. That feeling comes from hit frequency, not from a better price. The standard European version still costs 2.70% of total action over the long run.
From the Casino Side:
Odd/even bets are easy for the casino to settle but important for game speed. Outside bets attract players who want simple decisions and fast action. They also create repeat betting behavior: same side, same chip amount, spin after spin.
The dealer cares about clean placement before “no more bets.” The floor supervisor cares about table minimums, outside-bet maximums, and whether the dealer is paying even-money wagers correctly after zero. Surveillance pays attention when a player tries to claim a bet was on odd or even after the result is known, especially if chips were late or close to the line.
For the casino, odd/even is not dangerous. It is predictable action with a built-in edge. The only operational risk is bad procedure: late bets, unclear placement, or wrong zero-rule settlement.
Common Mistakes
- Treating odd/even as a true 50/50 bet.
- Forgetting that zero is neither odd nor even.
- Choosing American roulette when a European wheel is available.
- Increasing bet size after every loss because “odd must come soon.”
- Confusing hit frequency with lower house edge.
- Assuming even numbers are safer because the word “even” sounds balanced.
- Ignoring La Partage rules when comparing French roulette tables.
Hard Truth
Odd or even is almost a coin flip. Almost is where the casino lives.
FAQ
Is zero odd or even in roulette?
No. Zero is neither odd nor even for roulette betting. On standard tables, zero makes both odd and even lose.
What does odd or even pay in roulette?
Odd and even pay 1 to 1. A 10-unit winning bet earns 10 units profit, and the original 10-unit stake is returned.
What are the odds of winning an odd/even bet?
On European roulette, the chance is 18/37, or 48.65%. On American roulette, the chance is 18/38, or 47.37%.
Is odd/even better than red/black?
Mathematically, they are the same type of bet on a standard wheel. Both cover 18 numbers, pay 1 to 1, and lose on zero. Compare with red or black odds.
Does odd/even have a lower house edge?
No. On standard wheels, it has the same house edge as most other roulette bets: 2.70% European or 5.26% American.
Can odd or even come many times in a row?
Yes. Short streaks and ugly runs happen naturally. A streak does not force the opposite side to arrive next.
Is odd/even good for beginners?
It is easy to understand, but easy does not mean profitable. Beginners should focus on wheel selection, bet size, and total action, not guessing the “better” side.
Deeper Insight
Odd/even is a useful lesson in how roulette hides edge inside tiny differences. A player sees 18 odd numbers and 18 even numbers. That looks balanced. The missing part is the green pocket.
The casino does not need odd to be better than even. It only needs both to be worse than fair because of the zero. On a European wheel, a fair even-money bet would need one losing category for every winning category. Instead, odd has 18 winning outcomes and 19 losing outcomes. That extra losing outcome creates the 2.70% house edge.
On an American wheel, odd has 18 winning outcomes and 20 losing outcomes. The second green pocket doubles the damage. That is why the European vs American roulette page is not a minor preference issue. It is a cost issue.
The bet also creates a psychology trap. Because odd/even wins frequently, players often feel they are “controlling” the game. In reality, they are buying frequent small swings at a negative price. That is why progression systems on even-money bets are so popular — and why why roulette systems fail matters.
Formula / Calculation
Probability:
P(odd win) = favorable pockets / total pockets
European roulette:
P(odd win) = 18 / 37 = 0.486486 = 48.65%
American roulette:
P(odd win) = 18 / 38 = 0.473684 = 47.37%
Expected value for a 1-unit European odd bet:
EV = (18/37 × 1) - (19/37 × 1)
EV = -1/37 = -0.027027
House edge:
House Edge = -Player EV / Initial Stake = 2.70%
Formula Explanation in Plain English
On a European wheel, imagine 37 perfectly balanced spins where every pocket lands once. Odd wins 18 times and loses 19 times. If you bet 1 unit each time, you win 18 units but lose 19 units. That leaves you down 1 unit after 37 units wagered.
That one unit is the edge. It does not show up every session, but it is built into the bet.
Related Reading
Start with the full roulette guide if you want the game structure before individual bets. Then compare red or black odds, high or low odds, and roulette odds. For cost, read roulette house edge and test examples with the expected loss calculator or house edge calculator. If odd/even streaks are tempting you, read the roulette hot numbers myth.