No-Vig Calculator

How the calculation works

1. Each price becomes an implied probability. For American odds of -150 that is 150 / (150 + 100) = 60%; for +130 it is 100 / (130 + 100) = 43.5%.
2. The implied probabilities add up to more than 100% (here 103.5%). The extra is the book's margin, also called the vig, juice or overround.
3. Dividing each implied probability by that total scales them back to 100%: 60 / 103.5 = 58.0% and 43.5 / 103.5 = 42.0%. Those are the fair, or no-vig, probabilities.

Illustrative numbers, not a real game. This is the proportional (multiplicative) method — the same one the IntellaBets engine uses. Other methods (power, Shin) shift a little more of the margin onto longshots and give slightly different answers on lopsided markets.

What it can and cannot tell you

A fair probability from one book is that book's opinion with its fee taken out. It is not a forecast, and one book can simply be wrong. That is why IntellaBets averages the de-vigged prices of every book it tracks into a consensus, and only flags a price when it beats that consensus.

The optional comparison box shows the expected value of another book's price against the fair probability. Positive expected value is a statement about the price. Any single bet can still lose, and no calculator or service can guarantee a profit.

More on the method: How it works and Closing Line Value explained.