Fair Odds vs Sportsbook Odds
The price a sportsbook offers is not a pure statement of probability — it includes the book's margin. Estimated fair odds are what the price would look like with that margin removed.
The short answer
A -110/-110 market implies 52.38% on each side — 104.76% total. Scaling both sides back to 100% gives an estimated fair probability of 50% each, or +100 in fair odds. The gap between -110 (offered) and +100 (estimated fair) is the margin you pay.
How fair odds are estimated
EVScout removes the margin with proportional normalization: each side's implied probability is divided by the market's total implied probability. Where reliable sharp-market pricing is available, that market may be used as a stronger reference, because those markets often reflect more efficient price discovery. The result is always an estimate — no method reveals the true probability of a game.
Why the difference matters
Comparing the offered price to the estimated fair price is the core of every EVScout evaluation. Offered better than fair suggests positive estimated EV; offered worse means you are paying extra margin. It is a pricing comparison, not a prediction of who wins.
Try the math yourself
Fair Odds CalculatorWant this checked on a real ticket?
EVScout applies this math to every leg of your parlay automatically — estimated fair odds, estimated EV, sportsbook margin, and correlation warnings.
Evaluate My Parlay