Roulette EV Calculator
Calculate the expected value of any roulette bet. Compare American vs European wheels, factor in La Partage rules, and understand your mathematical expectation over any number of spins.
Formula:EV = (Win Probability × Win Amount) - (Lose Probability × Bet Amount)
Expected Value (EV)
-$0
House Edge
2.70%
Win Probability
48.65%
Bet Setup
$
Amount wagered per spin
Calculate EV over multiple spins
EV Calculation Breakdown
Win Probability48.6486%
Lose Probability51.3514%
Payout1:1
Win Amount$10
Loss Amount$10
Expected Win Value$5
Expected Loss Value-$5
Net EV Per Bet-$0
EV Comparison by Wheel Type
| Bet Type | European EV | American EV | Difference |
|---|---|---|---|
| Straight Up | -$0 | -$1 | $0 better |
| Split | -$0 | -$1 | $0 better |
| Street | -$0 | -$1 | $0 better |
| Corner | -$0 | -$1 | $0 better |
| Six Line | -$0 | -$1 | $0 better |
| Column | -$0 | -$1 | $0 better |
| Dozen | -$0 | -$1 | $0 better |
| Red | -$0 | -$1 | $0 better |
* All comparisons based on $10 bet. European wheel always has better EV due to single zero.
Quick Answer
A $10 bet on Red at a European wheel has an EV of -$0.27 (2.70% house edge). On an American wheel with double zero, the same bet has EV of -$0.53 (5.26% house edge).
Key Facts
- EV = (Win Probability x Payout) - (Lose Probability x Bet Amount)
- European wheel: Every $100 wagered loses $2.7 on average
- American wheel: Every $100 wagered loses $5.26 on average
- Negative EV is unavoidable - no bet or system can overcome it long-term
- La Partage/En Prison rules on even money bets cut house edge to 1.35%
- Over 1,000 spins, actual results converge toward expected value
Understanding Expected Value in Roulette
Expected Value (EV) is the mathematical average outcome of a bet over infinite repetitions. In roulette, EV is always negative because payouts are based on 36 numbers while the wheel has 37 (European) or 38 (American) numbers. The zero(s) give the house its edge.
The EV Formula
EV = (Probability of Winning × Payout) - (Probability of Losing × Bet Amount)
For a $10 bet on Red at European roulette:
- Win Probability: 18/37 = 48.65%
- Lose Probability: 19/37 = 51.35%
- EV = (0.4865 × $10) - (0.5135 × $10) = -$0
Frequently Asked Questions
What is Expected Value (EV) in roulette?
Expected Value is the average amount you can expect to win or lose per bet over the long run. For a $10 bet on Red at European roulette, EV = (18/37 x $10) - (19/37 x $10) = -$0.27. This means you lose $0.27 on average per $10 bet.
Why is roulette EV always negative?
Roulette EV is negative because of the zero (and double zero on American wheels). While payouts are calculated as if there were 36 numbers, there are actually 37 or 38. This gap creates the house edge - the casino's mathematical advantage on every bet.
Which roulette bets have the best EV?
On European roulette, all standard bets have the same -2.70% EV (except La Partage/En Prison even money bets at -1.35%). On American roulette, avoid the 5-number basket bet which has -7.89% EV. The best EV is European with La Partage at -1.35%.
Can betting systems overcome negative EV?
No betting system can overcome negative EV long-term. While systems like Martingale can win short-term, the math is inescapable: over enough spins, total losses approach the expected value. A $1,000 total wagered will average $27 loss on European and $52.60 loss on American roulette.
How do I calculate expected loss for a session?
Expected Loss = Total Wagered x House Edge. If you bet $25 per spin for 100 spins ($2,500 total) on European roulette, expected loss = $2,500 x 2.70% = $67.50. Actual results will vary, but this is the statistical average.
Try These Examples
Quick-start with common scenarios
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).
Expected Value (EV)
-$0
House Edge
2.70%
Win Probability
48.65%