Convert odds into implied probability and measure the bookmaker margin.
The overround is the share of fair total of 100 that sum of implied probabilities across all outcomes represents, expressed as a percentage. The same figure is also shown per 1,000 and as a "one in every N" odds statement, which is easier to reason about when the rate is very small. Absolute counts hide scale — a rate normalises the number so you can compare periods, channels or cohorts of different sizes, where lower is better.
Sports Betting Implied Probability
Bookmaker Overround = Sum of implied probabilities across all outcomes ÷ Fair total of 100 × 100
These figures are estimates based on population-average formulas and are intended for training and recreational planning only. They are not medical advice. Consult a qualified health professional before starting or changing an exercise programme, particularly if you have an existing medical condition.
Bookmaker Overround = Sum of implied probabilities across all outcomes ÷ Fair total of 100 × 100 The overround is the share of fair total of 100 that sum of implied probabilities across all outcomes represents, expressed as a percentage. The same figure is also shown per 1,000 and as a "one in every N" odds statement, which is easier to reason about when the rate is very small.
Absolute counts hide scale — a rate normalises the number so you can compare periods, channels or cohorts of different sizes, where lower is better.
This calculator takes 2 inputs: Sum of implied probabilities across all outcomes, Fair total of 100. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.