Use this explanation with the implied probability guide. The examples below are educational, use decimal notation and separate market data from editorial interpretation.
Two-sided no-vig example
Illustrative decimal prices normalized after removing the combined margin.
| Outcome | Raw probability | Normalized probability |
|---|---|---|
| Away at 1.80 | 55.56% | 52.63% |
| Home at 2.00 | 50.00% | 47.37% |
| Combined | 105.56% | 100.00% |
Convert each listed price
For decimal odds, divide one by the price. In the example, 1.80 converts to 55.56% and 2.00 converts to 50%. The raw probabilities total 105.56%, which is above 100% because the two-sided market includes margin.
Normalize the total
Divide each raw probability by 105.56%. The away side becomes about 52.63% and the home side about 47.37%. This removes the proportional margin from that pair of prices; it does not reveal the true probability.
Use matching outcomes
The calculation requires a complete set of mutually exclusive outcomes from the same market and timestamp. Do not combine one side from an old observation with the other side from a current row, or normalize different spread lines together.
- Convert all outcomes
- Add the raw probabilities
- Divide each result by the total
- Confirm the normalized set equals 100%
Common questions
Is no-vig probability the true chance?
No. It is a margin-adjusted market estimate. A research model may reasonably disagree with it.
Can no-vig math be used for spreads and totals?
Yes, when both sides use the exact same line and timestamp. Different handicaps or totals must not be normalized together.
Method: educational analysis reviewed against our data methodology and editorial policy. Illustrative prices are not current markets or recommendations.
