Bookmaker odds are skewed. They include a “Margin” (or Vigorish) that ensures the house wins. For example, if two teams have an equal chance of winning, the odds should be 2.00 / 2.00. Instead, you see 1.90 / 1.90.
This calculator removes the vigorish to show you the “True Odds” and the actual probability implied by the market. This is essential for comparing lines against your own models.
Why Remove the Vig?
Professional bettors don’t beat the bookmaker’s displayed odds; they beat the Fair Odds. If you don’t know the true market price without the fee, you can’t accurately calculate your edge.
Example: Finding True Probability
Market: NFL Spread. Odds: -110 / -110 (Decimal: 1.91 / 1.91).
- Implied Probability (with Vig): 52.3% each. Total = 104.6%.
- Fair Probability (No Vig): 50% each.
- Fair Odds: +100 (2.00).
This tool tells you that to break even on this bet, you don’t need to win 52.3% of the time (as the raw odds suggest); you are playing a 50/50 proposition where you pay a fee to enter.
Frequently Asked Questions (FAQ)
What is “Vig”?
Vig (short for Vigorish), also known as Juice or Margin, is the commission charged by a sportsbook for taking a bet. It is built directly into the odds.