Odds are a price, not a prediction. This tool translates a full market into the probability the bookmaker is quoting, adds the probabilities up, and shows you the margin — the built-in cost of every bet you place.
Convert each price to 1 ÷ odds, add them all up, subtract 1. The result is the margin or overround. 2.10/3.40/3.60 adds to 1.049 — a 4.9% margin.
Most Nigerian books run roughly 5% to 12% on football. Under 6% on a major league is competitive. Anything above 12% is expensive and costs you money on every single bet.
No. Margin guarantees an edge on the prices, not on the result — a book still loses on a bad weekend. But over thousands of bets, margin is what makes the book profitable and the punter unprofitable.