What is the vig in betting?
The vig (short for vigorish) is the bookmaker's built-in margin: the amount by which its prices pay out less than the true chances would justify. 'Juice' means the same thing in the US; 'margin' and 'overround' are the usual terms in Europe. You don't pay it as a separate fee: it's inside the odds.
How to calculate the vig from odds
Convert every outcome's odds to its implied probability (1 ÷ decimal odds), then add them up. In a fair market they would sum to exactly 100%. Any excess is the margin:
Overround = (sum of implied probabilities) − 1
Example: both sides at −110
A typical US point spread pays −110 on each side (1.909 in decimal). Each side implies 1 ÷ 1.909 = 52.38%, so the market adds up to 104.76%. The overround is 4.76%.
Example: a football 1X2 market
Odds of 2.10, 3.40 and 3.60 imply 47.62%, 29.41% and 27.78%. The total is 104.81%: an overround of 4.81%.
Our free vig calculator does this for any odds, in any format.
Overround vs hold: two numbers for the same fee
People mix these up. Overround compares the total to 100%. Hold is the share of all the money wagered that the bookmaker keeps if bets arrive evenly on every outcome:
Hold = overround ÷ (1 + overround)
At −110/−110, hold = 4.76 ÷ 104.76 = 4.55%. Stake 110 on each side (220 in total): one side wins and is paid 210 (stake plus 100 profit), so the bookmaker keeps 10 out of 220, which is 4.55%. A related number is the payout: 1 ÷ 1.0476 = 95.45% of the money comes back to bettors.
Why the vig matters to you
- It sets your break-even point. At −110 you need to win 52.38% of bets to break even, not 50%.
- It hides inside every price. A bet can look like value against the bookmaker's own odds and still be a poor bet once you remove the fee.
- It varies a lot. Bookmakers that welcome large stakes tend to run low margins on main lines; recreational bookmakers usually charge more, especially on props, long shots and accumulators, where the margin of each leg compounds.
What the vig costs you
If you bet 1,000 times with 10 on a true 50/50 market at −110, you stake 10,000 and expect to lose about 455: the 4.55% hold. A bettor with no edge pays the vig on every bet; a bettor with an edge has to overcome it first. At reduced-juice prices of −105 on both sides, the overround is 2.44% and the hold 2.38%: about half the cost for the same bet.
How to measure a bookmaker's real margin
Don't trust labels like 'best odds'. Take a sample of markets (main lines of a few popular events), enter every outcome's price in the vig calculator and average the overrounds. Do the same for props and for accumulators and you'll see where margin hides: it's usually higher on markets with less liquidity and on long shots.
How to remove the vig: no-vig odds
How to remove the vig: no-vig odds
To find what a market really thinks, take the margin out. At −110/−110 the answer is easy: 50% each, or +100. In general it isn't, because bookmakers don't spread the margin evenly: they usually load more of it onto long shots. The power method corrects for that, and the simple proportional method doesn't. Both are in our no-vig calculator, which explains why the choice matters.
Using the vig to choose where to bet
Lower margins mean better prices, so comparing bookmakers' margins on the same market is a quick filter (see line shopping). And because a sharp bookmaker's margin is small, its prices are the best base for a fair price against which to judge everyone else's.