Free Tool
No-Vig Fair Odds Calculator
Strip the bookmaker's hold from a two-sided market and see the true fair odds. The number you should be comparing every other book against.
Fair odds (no-vig)
Fair Over / Side A
-110
52.38% fair probability
Fair Under / Side B
-110
52.38% fair probability
Vig4.76%
Multiplicative vs. power method
The multiplicative method divides each implied probability by the overround — fast, intuitive, and the textbook standard. The power method solves for an exponent k where p₁k + p₂k = 1. Power tends to be more accurate on skewed two-way markets (e.g. heavy favorites) because the vig is rarely applied uniformly across both sides — the favorite often carries less hold. For balanced −110/−110 markets the two methods agree to within a fraction of a cent. Use power for pinpoint sharp-line estimates; multiplicative for quick mental math.