No-Vig & Fair Odds Calculator

What “no-vig” means

Traditional sportsbooks build a margin — the vig or overround — into their odds, so the implied probabilities of the two sides add up to more than 100%. That extra is the house’s edge. To find the fair probability of each side, you remove the margin proportionally: divide each side’s price by the combined total. If the two sides are 55¢ and 52¢ (107¢ combined), the fair probabilities are 55÷107 = 51.4% and 52÷107 = 48.6%.

Why it is useful

The no-vig price is the closest thing to an unbiased estimate of the true probability hidden in bookmaker odds — a useful benchmark to compare against a prediction-market price. If a regulated event contract trades below the fair no-vig price, it may be the better value. This is also why no-vig exchanges like Novig and ProphetX can offer better effective pricing: there is no margin baked in to start with. For the wider strategy, see arbitrage and no-vig trading, and to check for a guaranteed edge across venues, the arbitrage calculator.

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Frequently asked questions

What is a no-vig calculator?

It removes the bookmaker's margin (the vig) from two-sided odds to reveal the fair probability of each outcome. You enter the two prices, which sum to more than 100% because of the margin, and it returns each side's true, no-vig price.

How do you remove the vig?

You normalise the two implied probabilities so they sum to 100%, by dividing each side's price by the combined total. If the sides are 55 and 52 cents (107 combined), the fair probabilities are 55/107 = 51.4% and 52/107 = 48.6%.

Why is the no-vig price useful?

It is the closest thing to an unbiased estimate of the true probability hidden in bookmaker odds — a useful benchmark to compare against a regulated prediction-market price to spot better value.