The Vig Calculator shows the bookmaker’s margin (also called juice/overround) hidden in the odds. Enter the market odds and it returns the vig % plus the no-vig (fair) probabilities/odds. Use it to strip out the book’s edge, compare prices across books, and feed fair odds into your EV or Kelly calculations.
A vig calculator shows how much margin a bookmaker builds into a market and what the odds would be without it. Enter the American or decimal odds for every outcome (2 to 9 outcomes) and the calculator returns the vig %, the no-vig (fair) odds and the fair probability of each outcome.
The vig, also called juice or vigorish, is the bookmaker's built-in margin. In a fair market the implied probabilities of all outcomes add up to exactly 100%. Bookmakers price every outcome slightly shorter, so the implied probabilities add up to more than 100%. The excess is the overround, and the vig is the share of all stakes the bookmaker expects to keep.
Take a two-way market priced at −150 / +130:
Set the format to American and enter −150 and +130 to check the result.
The calculator converts every price to decimal odds and applies these formulas:
Implied probability = 1 ÷ decimal odds
Total implied probability (S) = sum of the implied probabilities of every outcome
Vig % = (S − 1) ÷ S × 100
Fair probability = implied probability − (S − 1) ÷ number of outcomes
No-vig odds = 1 ÷ fair probabilityThis calculator removes the margin additively: every outcome gives up an equal share of the overround. Other devigging methods, such as the proportional (multiplicative) or power methods, spread the margin differently and can produce slightly different fair odds, especially for long shots.
A standard −110/−110 line is 1.909 in decimal odds on each side. Each side implies 52.38%, so the total is 104.76%. The vig is 4.76 ÷ 104.76 = 4.55%, and removing it gives fair odds of 2.00 (+100) on each side, a 50% chance each.
The same calculation for a home, draw and away market:
| Outcome | Offered odds | Implied probability | Fair probability | No-vig odds |
|---|---|---|---|---|
| Home | 2.10 | 47.62% | 46.02% | 2.173 |
| Draw | 3.40 | 29.41% | 27.81% | 3.596 |
| Away | 3.60 | 27.78% | 26.17% | 3.820 |
Total implied probability: 104.81%. Overround: 4.81%. Vig: 4.59%.
The calculator accepts American odds directly, so you only need these formulas to convert by hand.
No-vig odds turn a bookmaker's prices into an estimate of each outcome's real chance. You can use them to:
OddsFantasy's positive EV finder does this automatically: it compares prices against no-vig odds from sharp bookmakers such as Pinnacle, and positive EV automation can place qualifying bets on Polymarket for you.
A −110/−110 line carries 4.55% vig. Lower-margin markets, such as those at sharp bookmakers and betting exchanges, give you better prices, while niche markets, props and futures often carry higher margins.
Yes. Switch the odds format to American and enter prices such as −110 or +150. The no-vig odds come back in American format too.
It is the share of total stakes the bookmaker expects to keep when money is spread across the outcomes in line with its prices. A 4.55% vig means the bookmaker expects to keep about 4.55 of every 100 staked on the market.
Overround is how far the total implied probability exceeds 100% (4.76% for −110/−110). Vig expresses the same margin as a share of that total (4.55%). This calculator reports the vig.
Yes. Juice, vig and vigorish all mean the bookmaker's margin.
Calculators remove the margin in different ways. This one takes an equal share of the overround from each outcome (the additive method); proportional and power methods spread it according to the odds, which mostly changes the fair odds of long shots.
Yes. Convert each outcome's share price into decimal odds with 1 ÷ price (a share at 0.45 is 2.222). If the prices you can buy at add up to more than 1.00, the excess works like a margin; it comes from the bid-ask spread rather than a bookmaker, and fees come on top.