Fair odds strip the vig out of a market so the implied probabilities add up to exactly 100%. They're the best estimate of what the sportsbook really thinks each outcome's chance is.
Sharp bettors use fair odds from efficient markets as a benchmark. If another sportsbook offers better odds than the fair price, the bet may have positive expected value.
The simplest method scales each side's implied probability by the same amount, so the market totals 100%.
How it works
To find fair odds, you need every side of the market. Convert each price to implied probability, add them up, then divide each side's probability by the total. The results add up to exactly 100%, and turning them back into odds gives the fair prices.
This is called the proportional (or multiplicative) method, and it's the most common. Other methods spread the margin differently, for example putting more of it on long shots, but the proportional method is a good starting point for most markets.
Fair odds are useful in two ways:
- Finding value. If you can bet at better odds than the fair price, the bet may have positive expected value.
- Setting expectations. They show what the market really thinks, which is useful when judging your own picks.
Fair odds are only as good as the market they come from. Prices from busy, efficient markets close to game time are much more reliable than early or thinly traded ones. The no-vig calculator does the maths for two- and three-way markets.
Examples
- Example 1
A market at -110 / -110 has fair odds of +100 (2.00) on each side.
- Example 2
A market at -150 / +130 adds up to 103.48%. Removing the margin gives fair chances of 57.98% and 42.02%, or about -138 / +138.
- Example 3
If the fair price on a team is +138 and another sportsbook offers +150, that bet is better than fair.
- Example 4
-110 / -110 has fair odds of +100 on each side, because both sides are equally likely once the margin is removed.
Common questions
How do you calculate no-vig odds?
Convert both sides to implied probability, divide each by the total so they add up to 100%, then convert those probabilities back into odds.
What are true odds in betting?
True odds are the fair odds of an outcome with no sportsbook margin. In practice, no-vig prices from an efficient market are the closest estimate.