Betting maths and calculators
What does a 25% bookmaker margin mean in a three-way football market?
Direct answer
If three quoted prices imply probabilities adding to 125%, the overround is 25 PERCENTAGE POINTS. That is not automatically a 25% loss on every bet; the expected loss at an individual price depends on its true outcome probability.
How to use this answer
This answer is based on the mathematical principle or published rule identified in the source below. If the question involves a live betting market, confirm its settlement definition before applying it to a specific bet.
If the three implied probabilities add to 125%, the overround is 25 percentage points; it is not directly equal to your realised loss on any single bet.
Use the precise stake, decimal odds, market terms and outcome probabilities when calculating the result. Expected value measures an average over hypothetical repetitions, not a guaranteed profit.