Overview

Sportsbooks bake a margin (vig, juice, or hold) into every market. A standard −110 / −110 two-way market implies 52.4% on each side, summing to 104.8% — the extra 4.8% is the book’s cut. The No-Vig Fair Odds Calculator strips out that margin to reveal the market’s implied probability and the corresponding fair price. Price-sensitive bettors use it to benchmark posted lines and review modeled edges.

The Formula

Formula: FairProb(A) = ImpliedProb(A) / (ImpliedProb(A) + ImpliedProb(B))

This is the proportional or multiplicative devig method. Alternative methods (additive, power, Shin) handle favorite-longshot bias differently, but proportional is the industry default.

When To Use It

Use it before placing any bet to see how much vig you are paying, to compare prices across books, and to evaluate +EV candidates. Pair it with the EV Calculator: any line shorter than the fair price may be worth reviewing for positive expected value.

Worked Example

Example 1: A market is posted at −120 / +100. Implied probabilities: 54.5% and 50.0%. Sum = 104.5% (4.5% hold). Fair probability for the favorite = 54.5 / 104.5 = 52.2%, which converts to a fair price of −109. If another book offers the favorite at −105, that price may be a +EV candidate.

Example 2: A three-way soccer market: Home −150 (60%), Draw +250 (28.6%), Away +280 (26.3%). Sum = 114.9% (huge 14.9% hold, common in soccer). Fair Home = 60 / 114.9 = 52.2%, fair Draw = 24.9%, fair Away = 22.9%. Always devig three-way markets before computing edges, or you will overestimate every bet.

Common Mistakes

• Using a single book’s line as "fair" — instead, average the no-vig lines from 3–5 trusted reference books (Pinnacle, Circa, Bookmaker).
• Forgetting to devig three-way markets, where hold is much higher.
• Mixing devig methods between bets, which produces inconsistent edge measurements.
• Treating heavy favorites as more accurate than longshots — proportional devig assumes both sides share the vig equally.