EV & Kelly Criterion Calculator
Free betting calculator for value bettors. Calculate expected value, remove bookmaker margin, and size your bets with Kelly Criterion. Used by professional bettors to maximize long-term edge.
What is Expected Value (EV)?
Expected value is the average outcome of a bet repeated over many trials.
The formula is simple: EV = (odds × probability) - 1.
A positive EV means you expect to profit long-term.
Example: odds 2.10, true probability 52%.
EV = (2.10 × 0.52) − 1 = +9.2% — a strong value bet.
At $100 stake, your expected profit per bet is $9.20.
Kelly Criterion Explained
Kelly Criterion calculates the mathematically optimal bet size to maximize bankroll growth.
Formula: f = (b×p − q) / b.
Professional bettors use Quarter Kelly (f × 0.25) to reduce variance while maintaining growth. Full Kelly maximizes expected log-growth but creates very large drawdowns.
Frequently Asked Questions
What EV percentage is a good value bet? +
Professional value bettors target EV above +2%. Edges of +1–3% are typical against sharp bookmakers like Pinnacle. Soft books occasionally offer 5–15% EV edges in the hours after line opening. EVBets only shows bets with EV above +1% and below +20% (higher values indicate data anomalies).
How do I find my true probability estimate? +
Use the No-Vig calculator to strip margin from 3+ bookmakers and average their fair probabilities. You can also use statistical models (Poisson distribution for football, Elo ratings for tennis) or compare against Betfair Exchange, which reflects the sharpest consensus.
Can I use this calculator for any sport? +
Yes. The EV formula and Kelly Criterion work for any sport with decimal odds: football (soccer), basketball, tennis, cricket, MMA, baseball, hockey, and more. For Asian handicap or totals markets, the principle is identical — enter the odds and your probability estimate.
What is the no-vig (fair odds) method? +
Bookmakers include a margin (vig/juice) in their odds so that implied probabilities add up to more than 100%. To find the true probability, we remove this margin proportionally. For a 3-way market with 108% overround: fair probability = implied probability / 1.08.