Roulette Odds Calculator
Calculate the probability and expected value for any roulette bet
Formula:Probability = Numbers Covered / Total Pockets
Bet Calculator
Select your wheel type and bet
Inside Bets
Outside Bets
Straight Up
2.70% chance
Covers 1 number
Payout
35:1
Win Amount
$350
EV per Bet
-$0
House Edge
2.7%
Win Probability2.70%
On average, this bet wins about 3 times out of 100 spins
Common Bets
Explore popular roulette bets
Quick Answer
Key concepts at a glance
Roulette odds depend on the wheel type and bet. European (single zero): straight bet wins 1 in 37 (2.7%), pays 35:1. American (double zero): straight wins 1 in 38 (2.63%), pays 35:1. Even-money bets (red/black) win 48.6% (European) or 47.4% (American). For a $10 straight bet: expected win = $350, probability = 2.7%, EV = -$0.27 (European).
Key Facts About Roulette Odds
Essential knowledge
- European wheel has 37 pockets (0-36), American has 38 (0, 00, 1-36)
- All bets have the same house edge on a given wheel (except five-number on American)
- European house edge: 2.70%, American: 5.26%
- Straight bet (single number) pays 35:1
- Even-money bets (red/black, odd/even, high/low) pay 1:1
- The five-number bet (American only) has worst odds: 7.89% house edge
- En prison/la partage rules reduce even-money house edge to 1.35%
Frequently Asked Questions
Common questions about roulette odds
What are the odds of hitting a single number?
On European roulette, each number has a 1/37 (2.70%) chance of hitting. On American roulette, it's 1/38 (2.63%). If you bet $10 on a single number and win, you get $350 plus your $10 back. Despite the 35:1 payout, the house edge makes this a negative expectation bet.
Which bets have the best odds?
On European wheels, all bets have the same 2.70% house edge except when en prison/la partage rules apply (reducing it to 1.35% on even-money bets). On American wheels, avoid the five-number bet (0, 00, 1, 2, 3) which has a 7.89% house edge. Otherwise, all American bets have 5.26% edge.
Is European or American roulette better?
European roulette is significantly better with 2.70% house edge vs 5.26% American. Over 1000 bets of $10, you expect to lose $27 on European vs $52.60 on American. Always choose European when available.
Do betting systems work in roulette?
No betting system can overcome the house edge. Martingale, Fibonacci, Labouchere, etc. may show short-term wins but mathematically cannot beat the odds. They often increase variance and risk of large losses. The house edge applies to every bet regardless of previous results.
How this works
Calculations follow the published mathematics of the game — combinatorics for cards, probability theory for dice, and expected-value accounting for wagers. Results are verified against independent references (primarily Wizard of Odds). No calculation here is an opinion or recommendation; it is arithmetic applied to the rules of the game.
What this tool can’t do
When to consult a professional
This tool computes probability and expected value. It is not a betting system and cannot predict the outcome of any individual wager. If gambling is causing problems for you or someone you know, call the National Problem Gambling Helpline at 1-800-GAMBLER.
Sources
- [1]Wizard of Odds — Michael Shackleford, ASAIndustrywizardofodds.comAccessed Apr 21, 2026
Actuary; widely cited casino-game probability reference. Used for house-edge and EV verification.
- [2]National Council on Problem GamblingOfficial sourcencpgambling.orgAccessed Apr 21, 2026
Responsible-gambling guidance and 1-800-GAMBLER helpline.
Joseph OrdunaFounder & Software Engineer
Full-stack software engineer specializing in embedded systems, web architecture, and AI/ML. Founder of Practical Web Tools. Built the gesture-controlled drone IP acquired by KD Interactive (Aura Drone, sold on Amazon).