Strategic

No-Vig (Fair Odds) Calculator

Enter the two sides of any market in American odds. Get the true vig-removed probability for each side plus the sportsbook hold percentage.

Side A Implied % 0%
Side A Fair % 0%
Side A Fair Odds +0
Side B Implied % 0%
Side B Fair % 0%
Side B Fair Odds +0
Sportsbook Hold 0%

What is "No-Vig" or "Fair Odds"?

Every sportsbook bakes a margin (the "vig" or "juice") into its odds. The standard -110/-110 spread implies 52.4%/52.4% = 104.8% total — the extra 4.8% is the hold. The no-vig calculation removes the vig and shows the sportsbook\'s true estimate of each side\'s win probability.

Why It Matters

Comparing the no-vig probability against your own model is the foundation of value betting. If the sportsbook\'s fair line says a team should win 55% but you believe they should win 60%, you have a 5% edge.

Line shopping across PA sportsbooks also benefits from no-vig comparison. If DraftKings posts a market with 4.5% hold and FanDuel posts the same market with 5.5% hold, the DraftKings price is sharper — you keep more of your expected value.

How the Math Works

  1. Convert each side from American to implied probability.
  2. Sum the two implied probabilities (this will exceed 100% by the hold amount).
  3. Divide each implied probability by the sum to get the fair probability.
  4. Convert the fair probability back to American odds (the "fair line").

Implied probability from American odds:

  • Negative (favorite): |American| / (|American| + 100). Example: -110 → 110/210 = 52.38%.
  • Positive (underdog): 100 / (American + 100). Example: +130 → 100/230 = 43.48%.

Worked Example

The Eagles are -180 home favorites over the Cowboys at +160. Implied probabilities: 64.29% (Eagles) + 38.46% (Cowboys) = 102.75% total. Hold = 2.75%.

Fair probabilities: 64.29 / 102.75 = 62.57% (Eagles) and 38.46 / 102.75 = 37.43% (Cowboys). Fair lines: Eagles −167, Cowboys +167.

If your model says the Eagles win 65%, you have a 2.4% edge on the Eagles moneyline at the posted price.

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