No-Vig Calculator: fair odds without the juice

Every sportsbook builds a fee into its odds. That fee is the vig, also called the juice or the margin. You never see it as a line item, but it is there in every two-sided market: if you convert both prices to implied probabilities and add them up, the total comes out above 100%. A fair market would sum to exactly 100%, so everything above that line is the book paying itself.

Take the classic -110/-110 spread. At -110, you risk 110 to win 100, which implies a win probability of 110/210, or 52.38%. Both sides at -110 means the market totals 104.76%. That extra 4.76% is the overround, and it is why betting sides at random loses money over time: you are paying 52.38% prices for 50% outcomes.

Devigging strips that fee back out. Divide each implied probability by the total and the two sides are normalized to sum to exactly 100%. For -110/-110, each side becomes 52.38 / 104.76, which is exactly 50%, and 50% converts back to fair odds of +100 on each side. Now you know what the market actually thinks, separate from what the book charges. That fair number is the honest benchmark for every bet you consider. If the fair probability of a side is 50% and one book will pay you +105, you have found positive expected value. If the best price out there is -115, you are paying more than the outcome is worth, no matter how good the pick feels.

Doing this by hand for one market is easy. Doing it across every game, every market, and every book, all day, is not. OddSightSeer automates the whole loop: we pull real-time odds from 20+ sportsbooks, de-vig every two-sided quote, weight sharp books like Pinnacle, Novig, and ProphetX heavier, and publish a true EV% on every pick, with the best price highlighted so you always know where to bet it. This calculator is the single-market version of that engine, free for whenever you want to check a number yourself.