BETTING MATH · ODDS
Betting margin calculator
Enter decimal odds for each outcome to calculate the implied probability total and bookmaker overround.
BOOKMAKER OVERROUND
0%
Sum of implied probabilities minus 100%
Implied probability total 0%
Outcome 1 probability 0%
Outcome 2 probability 0%
Outcome 3 probability —
How betting margin is calculated
For decimal odds, implied probability is one divided by the odds. Add each outcome probability, then subtract 100% to find overround.
Overround = (1 ÷ odds₁ + 1 ÷ odds₂ + … − 1) × 100
Static examples
| Odds | Implied total | Overround |
|---|---|---|
| 2.00 / 2.00 | 100% | 0% |
| 1.91 / 1.91 | 104.71% | 4.71% |
| 2.50 / 3.20 / 2.80 | 107.04% | 7.04% |