Sum of implied probabilities from posted odds (e.g., 1/oA + 1/oB). Over 100% reflects the book’s margin.

How to get no-vig probabilities?

Invert odds to probabilities, sum them and divide each by the sum. For 1X2, do the same across H/D/A.

Fair odds are just 1 / (no-vig probability).

No-vig Odds (Remove Margin)

Back to the calculator.

Open No-Vig Calculator (Edge Finder) Paste sharp prices → get fair p/odds, EV% & Kelly instantly.

Bookmaker decimal odds include margin (overround). To get fair probabilities, invert odds and re-normalize.

Let odds be oA, oB. Then

overround = 1/oA + 1/oB, margin = overround − 1

pA = (1/oA) / overround, pB = (1/oB) / overround

Fair odds: fairA = 1/pA, fairB = 1/pB.

Sum inverted odds across H/D/A and divide each by the sum; invert for fair odds.

Our calculator also shows “Spread %”, each side’s contribution (1/o − p); sums to margin.