What are no-vig (fair) odds?
No-vig odds are a bookmaker's odds with its margin taken out. The margin, called the vig, juice or overround, is how a bookmaker makes money: it sets the odds so that the probabilities behind them add up to more than 100%.
Take the over/under 2.5 goals market at 1.90 and 1.95. Those odds imply 52.63% and 51.28%, which add up to 103.91%. The extra 3.91% is the margin. Remove it and you get fair probabilities of 50.65% and 49.35%, and fair odds of 1.97 and 2.03.
Why fair odds matter
Fair odds show what a bookmaker really thinks of a match, without its fee on top. That makes them a baseline for two things.
- Finding value. If you think a team wins more often than its fair probability says, odds above the fair odds are worth taking. Odds below fair odds need an even bigger edge to pay.
- Comparing bookmakers. A bookmaker with higher odds on one outcome may just have a bigger margin elsewhere. Comparing fair odds shows who is really out of line.
- Judging odds against the market. Take the fair odds of a sharp bookmaker, then check if a softer one is offering more. That gap is where most value bets start.
Odds Outliers does this across every bookmaker we track, so you don't have to enter the odds by hand.
How to use the no-vig calculator
- 1
Pick 2-way or 3-way. 2-way for over/under, both teams to score or a player prop. 3-way for the match result. Use Add outcome for markets with more, up to 6.
- 2
Enter the odds for every outcome. Take them from one bookmaker. Decimal, fractional and American odds all work.
- 3
Read the fair odds. Each row shows the implied probability, the fair probability and the fair odds. The panel shows the market total and the margin.
- 4
Check the method. Proportional is the default. Switch to power on a lopsided market and compare.
How to remove the vig
Turn each odds into an implied probability, add them up, then scale them back to 100%.
Implied probability = 1 ÷ odds
Market total = sum of every implied probability
Margin = market total minus 100%
Proportional fair probability = implied probability ÷ market total
Power fair probability = implied probability ^ k, with k chosen so they add up to 100%
Fair odds = 1 ÷ fair probability
The proportional method takes the same share off every outcome. The power method uses an exponent k above 1, which shrinks small probabilities by a larger share, so the long odds lose more. You can't solve k by hand, so the calculator does it for you.
Examples
Load any example into the calculator to change the odds.
Over/under 2.5 goals
A bookmaker offers 1.90 on over 2.5 goals and 1.95 on under. The two add up to more than 100%, and the margin is the gap.
| Outcome | Odds | Fair | Fair odds |
|---|---|---|---|
| Over 2.5 | 1.90 | 50.65% | 1.97 |
| Under 2.5 | 1.95 | 49.35% | 2.03 |
The odds add up to 103.91%, a margin of 3.91%.
Match result
Home 2.10, draw 3.40, away 3.60. Football 1X2 markets are 3-way, so all three outcomes go in together.
| Outcome | Odds | Fair | Fair odds |
|---|---|---|---|
| Home | 2.10 | 45.43% | 2.20 |
| Draw | 3.40 | 28.06% | 3.56 |
| Away | 3.60 | 26.50% | 3.77 |
The odds add up to 104.81%, a margin of 4.81%.
Big favorite, power method
A top side at home against a promoted team: 1.25, 6.50 and 13.00. With a favorite this strong the method matters, because the long odds carry more of the margin.
| Outcome | Odds | Fair | Fair odds |
|---|---|---|---|
| Home | 1.25 | 79.14% | 1.26 |
| Draw | 6.50 | 14.06% | 7.11 |
| Away | 13.00 | 6.80% | 14.71 |
The odds add up to 103.08%, a margin of 3.08%. The proportional method gives the away team 13.40 instead of 14.71.
Common mistakes
- Leaving an outcome out. A 3-way market needs all three odds. With only two, the total is too low and the margin shows as negative.
- Mixing bookmakers. Fair odds only make sense when every outcome comes from the same bookmaker at the same time. Odds from different bookmakers measure an arbitrage, not a margin.
- Treating fair odds as the truth. They are the bookmaker's view without its fee. A soft bookmaker's fair odds can still be wrong.
- Comparing a no-vig number to odds with the margin in. Compare fair odds to fair odds, or your odds to fair odds. Never a fair probability to an implied one.
- Using it on a market with a push. Asian lines with a refund on a draw have three results. Enter the odds as they are only if the market has no refund outcome.