# No-Vig Calculator

Remove the bookmaker margin from any 2-way or 3-way market. Enter the odds in American, decimal or fractional format to see the vig, the hold and the fair odds for each outcome.

[No-Vig Calculator](https://odds-api.io/tools/no-vig-calculator): Auto-detect reads 5/2 as fractional, -110 or +150 as American and 1.91 as decimal. Multiplicative: Scales every implied probability down by the same factor. The usual default. Additive: Takes the same number of percentage points off every outcome. Power: Raises each probability to one shared power, so longshots lose more of their price. Shin: Treats the margin as cover against informed bettors. Same as additive on 2-way markets.

## What is the vig?

The vig, short for vigorish and also called juice or margin, is the cut a bookmaker builds into its prices. Turn every outcome of a market into an implied probability and the total comes to more than 100%. The extra is the vig.

A standard point spread priced at -110 on both sides is the classic case. Each side implies 52.38%, the two add up to 104.76%, and the bookmaker keeps about 4.5% of all money staked if the action is balanced. No-vig odds are the prices you would see with that margin taken out.

## Vig, hold and overround

Three numbers describe the same margin. The booksum is the sum of the implied probabilities. The overround is the booksum minus 100%, so 4.76% at -110 / -110. The hold is the share of total stakes the bookmaker keeps on a balanced book: 1 - 1 / booksum, which is 4.55% at -110 / -110.

US books usually quote the hold and call it the vig. European sites often quote the overround or the payout (100% minus the hold). The calculator shows all three, so you can compare a number with whatever source you are reading.

## The no-vig formula

For the multiplicative method, with decimal odds o for each outcome:

- `implied probability = 1 / o`
- `booksum = sum of all implied probabilities`
- `fair probability = implied probability / booksum`
- `fair odds = 1 / fair probability`

American odds convert to decimal first: +150 is 1 + 150 / 100 = 2.50, and -150 is 1 + 100 / 150 = 1.667. A fraction like 5/2 is 1 + 5 / 2 = 3.50.

## Worked example: -150 / +130

A two-way moneyline with the favourite at -150 and the underdog at +130.

1. -150 is 1.667 in decimal, an implied probability of 60.00%.
2. +130 is 2.30 in decimal, an implied probability of 43.48%.
3. The booksum is 103.48%, so the overround is 3.48% and the vig (hold) is 3.36%.
4. Divide each probability by 1.0348: the favourite is 57.98% and the underdog 42.02%.
5. Fair odds are 1 / 0.5798 = 1.725 (-138) and 1 / 0.4202 = 2.380 (+138).

### Three-way example

A football match result priced 2.10 / 3.40 / 3.60 has a booksum of 104.81% and a vig of 4.59%. With the multiplicative method the fair probabilities are 45.43%, 28.06% and 26.50%, which gives fair odds of 2.20, 3.56 and 3.77. The power and Shin methods move a little more of the margin onto the draw and the away side, so the home win comes out shorter.

## Which de-vig method should you use?

Each method answers the same question, how the bookmaker spread its margin across the outcomes, with a different assumption.

### Multiplicative

Multiplicative (also called proportional or normalisation) divides each implied probability by the booksum. Every outcome loses the same share of its probability. It is simple, it never fails, and it is what most calculators and odds screens use.

### Additive

Additive takes the same number of percentage points off each outcome. In relative terms that hits longshots hardest, and with a big margin it can push a longshot below zero, in which case it has no answer.

### Power

Power finds one exponent k and raises every implied probability to it so the results add up to 100%. Longshots lose more of their price than favourites, which fits the favourite-longshot bias seen in most betting markets.

### Shin

Shin comes from a 1990s model where the bookmaker widens prices to protect itself from bettors with better information. On 2-way markets it gives the same result as additive. On 3-way markets it usually sits between multiplicative and power.

- Close to even, such as spreads and totals at around -110 each way: all four methods give almost the same answer, so multiplicative is fine.
- A clear favourite, three-way football results, or any market with a long price: power or Shin usually give a more realistic fair price for the longshot.
- Not sure: compare the four columns in the table. If they agree, the method does not matter for that market. If they differ, the gap tells you how much the answer depends on the assumption.

## Fair odds for every market through the API

Working this out by hand is fine for one price. To do it for every match, the `/v3/odds/summary` endpoint returns a `fair` price for each outcome of each market line, built from the de-vigged prices of at least three bookmakers, next to the best, average, median and worst price across 450+ bookmakers.

```javascript
const url = 'https://api.odds-api.io/v3/odds/summary'
  + `?apiKey=${API_KEY}&eventId=${eventId}&markets=ML`
const summary = await (await fetch(url)).json()
const line = summary.markets.find((m) => m.name === 'ML').lines[0]

for (const [side, price] of Object.entries(line.outcomes)) {
  console.log(side, 'best', price.best, 'fair', price.fair)
}
```

```json
{
  "name": "ML",
  "lines": [{
    "main": true,
    "books": 23,
    "fairBooks": 21,
    "outcomes": {
      "home": { "best": 3.9, "average": 3.38, "fair": 3.65 },
      "draw": { "best": 3.2, "average": 3.04, "fair": 3.45 },
      "away": { "best": 2.2, "average": 2.08, "fair": 2.3 }
    }
  }]
}
```

Market names such as ML, Spread and Totals are listed for every sport on the [betting markets](https://odds-api.io/markets) page. The odds summary is part of Growth plans and above.

[Odds summary guide](https://docs.odds-api.io/guides/odds-summary) · [See plans](https://odds-api.io/pricing)

## Frequently asked questions

### What does no-vig mean?

No-vig odds are the prices a market would show without the bookmaker margin. The implied probabilities of all outcomes add up to exactly 100%, so they are the best estimate of what the market thinks will happen.

### How do you calculate no-vig odds?

Convert each price to an implied probability (1 divided by the decimal odds), add them up, then divide each probability by that total. One divided by the result is the fair decimal price. The calculator above does this and also offers the additive, power and Shin methods.

### How much vig is there on -110 odds?

A market priced -110 on both sides has a hold of 4.55% and an overround of 4.76%. Each side implies 52.38%, and the fair price of each side is +100, or 2.00 in decimal.

### Is the vig the same as the hold?

In US betting the two words usually mean the same number: 1 - 1 / booksum, the share of all stakes a bookmaker keeps on a balanced book. Overround is a different figure for the same margin, the booksum minus 100%, and it is always a little larger.

### Which no-vig method is the most accurate?

Štrumbelj (2014, International Journal of Forecasting) found that Shin's method gave more accurate probabilities than basic normalisation, the multiplicative method. Bookmakers tend to put more margin on longshots, and Shin and power both allow for that. For balanced 2-way markets the methods barely differ.

### Does a fair price mean a bet will win?

No. Fair odds are an estimate of the probability the market gives each outcome, with the margin taken out. Comparing a price to the fair price tells you whether it is above or below that estimate. It says nothing certain about a single result.

### Can I get no-vig odds from an API?

Yes. The Odds-API.io odds summary endpoint returns a fair price for each outcome of each market line, built from the de-vigged prices of several bookmakers, alongside the best and average odds.

## Related

- [Margin calculator](https://odds-api.io/tools/margin-calculator)
- [Odds converter](https://odds-api.io/tools/odds-converter)
- [What is implied probability?](https://odds-api.io/glossary/implied-probability)
- [What is value betting?](https://odds-api.io/glossary/value-betting)

Fair odds describe a market, they do not predict a result. If you bet, set a limit you can afford to lose.

Last updated November 13, 2026

Link to this page: https://odds-api.io/tools/no-vig-calculator