No-vig calculator

What the vig is

Every price a bookmaker offers has its margin built in. The vig (short for vigorish, also called juice, margin or overround) is the bookmaker’s cut for making the market. You can see it by turning the prices into probabilities: honest odds on every outcome of a market would add up to exactly 100%, and a bookmaker’s add up to more. The extra is the margin.

A coin-flip market shows it plainly. Fair odds would be 2.00 on each side. A bookmaker offers 1.90 on each, which implies 52.63% twice, 105.26% in total: a 5.26% overround. Take equal bets on both sides at 1.90 and the book keeps 0.10 of every 2.00 staked, a 5% return whichever side wins.

How removing it works

Three steps, and the calculator does all of them for you:

1. Convert each price to an implied probability: 1 divided by the decimal odds. American and fractional prices are converted to decimal first.
2. Add the implied probabilities. The total is the overround; the amount over 100% is the margin.
3. Scale the probabilities back down so they add up to exactly 100%. Those are the fair probabilities, and 1 divided by each one is the fair (no-vig) price.

The only real choice is in step three: how much of the margin to take off each outcome. That is where the two methods differ.

The two methods

Proportional divides every implied probability by the overround, so each outcome gives back margin in the same ratio. It is simple and close enough on markets near 50/50. It is sometimes described as removing the vig equally.

Logarithmic raises every implied probability to the same power, chosen so the results add up to 100%. Because a power shrinks small probabilities more than large ones, more of the margin comes off the longer price. That matches how bookmakers actually price lopsided markets: they load more margin onto the underdog, a pattern known as the favourite-longshot bias. This is the method OddsHub uses for every fair price on the site and in the Terminal, so the numbers here match the ones you see there.

A worked example

Take a lopsided tennis moneyline from a sharp bookmaker at 1.110 and 7.670. The implied probabilities are 90.09% and 13.04%, 103.13% together, so the margin is 3.13%.

• Proportional removal gives fair odds of 1.145 and 7.910.
• Logarithmic removal gives 1.121 and 9.275.

The difference matters the moment you compare a price. Say another bookmaker offers 8.20 on the underdog. Against the proportional fair price of 7.910 it looks like a value bet. Against the logarithmic 9.275 it is a clear loser. Same market, same margin, opposite decision. Type 1.110 and 7.670 into the calculator and switch between the methods to see it.

When to use it

• Checking a price for value. De-vig a sharp book’s market, then any price above the fair odds at your own bookmaker is positive expected value. The free value bets page runs that comparison across every bookmaker for you.
• Measuring closing line value. The fairest benchmark for a bet is the no-vig closing price. The CLV calculator takes the other side of the closing market and removes the margin with the same method.
• Comparing bookmakers. The margin itself tells you how much a book charges. Line shopping across 450+ bookmakers on OddsHub’s odds comparison keeps more of it in your pocket.
• Reading a move. When a sharp price drops, the question is whether a slower bookmaker is still above the new fair price. See how to read line movement.

For the full story on margins, how they shrink toward kickoff and why the distribution method matters, read the guide to the no-vig odds calculator and what fair odds mean.

Fair prices on every market, automatically

Doing this by hand for one market is quick. Doing it for every market you might bet is not. The OddsHub Terminal shows the logarithmic fair price beside every drop and ranks value bets at your bookmakers against it. The free plan runs 15 minutes behind the live feed and includes the full bet tracker with automatic CLV.