Value Betting Calculator (+ Kelly Criterion)
Identify profitable betting opportunities by calculating Expected Value (EV). Includes a Kelly Criterion tool to determine the optimal stake size based on your calculated edge.
Input Data
About
In the world of probability and statistics, 'Value' exists when the probability of an outcome is higher than the probability implied by the odds offered. Professional risk managers and bettors do not rely on hunches; they rely on Positive Expected Value (+EV).
This tool performs two critical functions: First, it compares the Bookmaker's Odds against your Assumed True Probability to determine if a value edge exists. Second, if an edge is found, it uses the Kelly Criterion—a formula used by financial investors to maximize logarithmic wealth—to suggest exactly how much of your bankroll should be risked on that specific event to balance growth and safety.
Formulas
1. Value Calculation:
2. Kelly Criterion (Optimal Stake):
Where b is (Odds - 1), p is probability of winning, and q is probability of losing (1-p).
Reference Data
| Decimal Odds | Implied Probability | Breakeven % |
|---|---|---|
| 1.10 | 90.9% | Requires >91% win rate |
| 1.50 | 66.7% | Requires >67% win rate |
| 2.00 | 50.0% | Requires >50% win rate (Coin Flip) |
| 2.50 | 40.0% | Requires >40% win rate |
| 3.00 | 33.3% | Requires >33.3% win rate |
| 5.00 | 20.0% | Requires >20% win rate |
| 10.00 | 10.0% | Requires >10% win rate |
| 100.00 | 1.0% | Long shot |