EV Calculator

What is Expected Value (EV)?

Expected Value is the average long-term profit or loss of a bet. Repeatedly placing +EV bets leads to long-term profit.

Formula: EV = (probability × profit) - ((1-probability) × stake)

What is the Kelly Criterion?

The Kelly criterion mathematically determines the optimal bet size based on your edge.

Formula: f* = (bp - q) / b (b = odds-1, p = win prob, q = loss prob)

• Full Kelly — Maximum growth rate but high volatility. For pros only
• Half Kelly — Recommended. Optimal balance of growth and risk
• Quarter Kelly — Conservative. For beginners or high uncertainty

Calculating Edge

Edge = (win probability × decimal odds - 1) × 100%. Only bet when you have a positive edge. Having an edge that exceeds the bookmaker's margin is the key to long-term profit.