What Is the Vig? How to Remove It and Find Fair Odds

Every price a bookmaker offers is shaded in their favour. That built-in margin — the vig (short for vigorish), also called the juice or overround — is why the odds on a market add up to more than 100%. If you want to know whether a bet is actually good value, the first thing you have to do is strip the vig out. Here's how.

What the vig actually is

Take a coin-flip market priced at 1.90 / 1.90. The implied probability of each side is 1 / 1.90 = 52.6%. Add them together and you get 105.3% — but a real market can only be 100%. That extra 5.3% is the vig: the bookmaker's margin, and your long-run cost of doing business.

You can measure it on any market with a bookmaker margin calculator: add up 1/odds for every outcome, subtract 100%, and that's the vig. Sharp books like Pinnacle run 2–3% on main markets; soft books are often 5–8% or more.

Why removing the vig matters

The vig hides the market's true opinion. To find value, you need the fair, no-vig odds — the price that would exist if the bookmaker took no margin. That fair price is the best available estimate of an outcome's true probability, and it's the benchmark you compare every other price against.

How to remove the vig (devigging)

Devigging means rescaling the implied probabilities so they sum to exactly 100%. There are two common methods:

• Multiplicative (normalisation): divide each outcome's implied probability by the total overround. Simple and fast.
• Logarithmic / power methods: adjust for favourite–longshot bias, where the margin sits more heavily on longshots. More accurate on lopsided markets.

You don't have to do the maths by hand — our free no-vig calculator takes the raw odds and returns the fair price and true probability of each outcome using the logarithmic method.

Turning fair odds into value

Once you have the no-vig fair odds from a sharp book, the play is simple: if a soft bookmaker offers longer odds than that fair price, the bet is +EV. Plug both numbers into an EV calculator to see the exact edge. Do this consistently and track your closing line value, and you'll know within weeks whether you're beating the market.