No-vig calculator
A sportsbook’s prices for every outcome of a market imply more than 100% in total; the excess is its margin (the vig). Removing it gives no-vig, or fair, probabilities. By the multiplicative method used here, each outcome’s implied probability is divided by the total: −110 / −110 becomes 50% / 50%, with a hold of 4.55%.
Remove the vig
Use the prices of one sportsbook for every outcome of the same market and line. Prices from different sportsbooks can add up to less than 100%, and then there is no margin to remove.
The method
Implied probability of each outcome: p = 1 ÷ decimal odds.
Total (the book): T = sum of every outcome’s p.
Overround = T − 1: the margin as points over 100%.
Hold = 1 − 1 ÷ T: the share of all money staked that the sportsbook keeps when money is staked on each outcome in proportion to its implied probability.
No-vig probability of each outcome = p ÷ T. Fair odds = 1 ÷ no-vig probability.
A market at −150 / +130. Implied probabilities: 60.00% and 43.48%, total 103.48%. Overround 3.48%; hold 1 − 1 ÷ 1.0348 = 3.36%. No-vig probabilities: 60.00% ÷ 103.48% = 57.98% and 42.02%. Fair odds: −138 and +138 (decimal 1.725 and 2.38).
Overround and hold measure the same margin two ways, and both are called the vig. At −110 / −110 the overround is 4.76% and the hold 4.55%. The calculator shows both.
This multiplicative (proportional) method is the one StatsNext uses for no-vig probabilities in the app.
Other ways to remove the margin
The multiplicative method assumes the margin is spread over the outcomes in proportion to their implied probabilities. That is a convention, not a fact about how any sportsbook sets prices. Other methods make different assumptions and give slightly different answers:
- Additive: subtracts an equal share of the margin from each outcome.
- Power: raises each implied probability to the same power, chosen so they add up to exactly 100%. It takes more of the margin from longshots.
- Shin: models a share of bettors with better information and solves for the probabilities under that model; it also takes more from longshots.
When both sides are priced the same, every method gives 50% / 50%. The methods differ most when one side is a heavy favorite or the market has many outcomes; for two-way markets with typical margins, the difference is often around a percentage point or less. None of them reveals the true probability; each is an estimate of what the prices would be without the margin.
Worked examples
| Prices | Total implied | Hold | No-vig probabilities | Fair American |
|---|---|---|---|---|
| −110 / −110 | 104.76% | 4.55% | 50.00% / 50.00% | +100 / +100 |
| −120 / +100 | 104.55% | 4.35% | 52.17% / 47.83% | −109 / +109 |
| −150 / +130 | 103.48% | 3.36% | 57.98% / 42.02% | −138 / +138 |
| −200 / +170 | 103.70% | 3.57% | 64.29% / 35.71% | −180 / +180 |
| −300 / +250 | 103.57% | 3.45% | 72.41% / 27.59% | −263 / +263 |
| Prices | Total implied | Hold | No-vig probabilities | Fair American |
|---|---|---|---|---|
| +150 / +230 / +190 | 104.79% | 4.57% | 38.17% / 28.92% / 32.91% | +162 / +246 / +204 |
In the three-way example (decimal 2.50, 3.30, 2.90), the three outcomes imply 104.79% together, and the hold is 4.57%.
Questions
Are no-vig probabilities the true probabilities?
No. They are the sportsbook’s prices with its margin taken out by one convention. They show what the market implies, which can be wrong, and a different method gives slightly different numbers.
What is the difference between hold and overround?
Overround is how far the implied probabilities exceed 100% (T − 1). Hold is the share of all money staked the sportsbook would keep if its action matched its prices (1 − 1 ÷ T). For −110 / −110 they are 4.76% and 4.55%.
Why did I get a negative hold?
Your prices imply less than 100% in total. That does not happen within one sportsbook’s market; it usually means the prices come from different sportsbooks or different lines.
Can I use it for a market with more than three outcomes?
The method works for any number of outcomes, but this calculator takes two or three. For futures with many outcomes, the margin is usually much larger and harder to remove fairly.
Arithmetic, not advice
These calculators do arithmetic on the numbers you enter. They do not know the true chance of any result, they do not predict outcomes, and using them does not make betting profitable. Betting involves financial risk, and no research or model makes gambling safe or removes that risk.
StatsNext is for people 18 and older. Being 18 or older does not mean sports betting is legal for you: follow the laws and legal gambling age requirements where you live. Never wager money you cannot afford to lose, and do not chase losses. If gambling stops feeling like it is within your limits, free and confidential help is available 24/7 from the National Problem Gambling Helpline: 1-800-MY-RESET (1-800-697-3738). More resources are on the Responsible Gambling page.
StatsNext is a research platform, not a sportsbook; it does not accept wagers or guarantee results (Research Disclaimer, Responsible Gambling).
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