EV Calculator

Calculate expected value and optimal position size using Kelly criterion.

Your Estimated Probability

55%

What you believe the true probability is

Market Odds

Bankroll

Positive EV

+5.00%

Expected return per $1 wagered

Your Edge

+2.6%

Your probability (55%) vs implied (52.4%)

Kelly Criterion Sizing

Full Kelly5.5% = $550

Half Kelly (recommended)2.8% = $275

Quarter Kelly1.4% = $138

Odds Conversion

Decimal

1.909

Implied Prob

52.4%

American

-110

Expected Value (EV) = (Your Probability x Payout) - (1 - Your Probability). Positive EV means the bet is profitable long-term.

Kelly Criterion determines optimal bet size to maximize long-term growth. Half Kelly is recommended as it provides ~75% of growth with much lower variance.

Edge = Your estimated probability minus the market's implied probability. A positive edge means you believe the market is mispricing the event.