No-Vig (Fair Odds) Calculator
Remove the sportsbook's margin to reveal the true probability behind any 2-way line.
The Two Sides
Both sides of a 2-way market (e.g. Over/Under or spread).
-110 · 1.91 · 10/11 · 52.4%
-110 · 1.91 · 10/11 · 52.4%
True "Fair" Odds
Sportsbook vig: 4.71%
Side 1 fair value
+10050.00%
Side 2 fair value
+10050.00%
How to use this tool
- Enter both sides of a 2-way market in any odds format.
- Read off the vig and the fair (no-vig) probability for each side.
- Compare the fair probability to a prediction-market price to spot mispriced outcomes.
The formula
true pᵢ = impliedᵢ / (implied₁ + implied₂) · vig = (Σ implied) − 100%- impliedᵢ = 1 / decimalᵢ
- Normalisation removes the book's overround
Worked example
−110 / −110 each imply 52.38%, summing to 104.76% — a 4.76% vig. Normalised, the fair price for each side is 50.00% (even money / +100).
Edge detection: a sharp book's no-vig line and a liquid prediction-market price are both near-fair probability estimates. When a soft book's no-vig number disagrees with the market, that gap is where +EV bets live.