No VIG Calculator

No VIG (Fair Play) Odds Calculator

Strip out the bookmaker's commission (vigourish/juice) to calculate the true, unbiased probabilities and fair market betting odds.

Fair Value Market Metrics

Option A True Odds +100

Option B True Odds +100

Option A Fair Probability 50.00%

Option B Fair Probability 50.00%

Total Overround (Juice) 4.76%

Standard House Edge 4.55%

What is "No Vig" Odds Calculation?

In sports betting, the "vig" (short for vigourish, also known as the juice, margin, or overround) is the premium fee or commission that a bookmaker charges for accepting a wager. Sportsbooks build this commission directly into their public-facing odds. To discover the actual, fair-market expectation of a matchup, professional bettors remove this fee to uncover the **No-Vig Odds** and the true underlying mathematical probabilities.

The Mathematics Behind Removing Sportsbook Juice

When wagers are placed on both sides of an outcome, the bookmaker aims to balance liabilities and secure a risk-free margin. This is achieved by creating implied probabilities that sum to greater than $100\%$. The excess over $100\%$ represents the sportsbook's built-in commission.

Step 1: Convert American Odds ($A$) to Implied Probability ($P$)

The conversion depends on whether the odds are negative (favorites) or positive (underdogs):

$$P = \begin{cases} \frac{|A|}{|A| + 100} & \text{if } A < 0 \\ \frac{100}{A + 100} & \text{if } A \ge 100 \end{cases}$$

Step 2: Calculate the Total Overround ($S$)

The sum of all public implied probabilities represents the overround:

$$S = P_A + P_B$$

The *Vigourish* (commission percentage of the total pool) is derived as:

$$\text{Vig} = 1 - \frac{1}{S} = \frac{S - 1}{S}$$

Step 3: Normalize to Find the Fair Probability ($P'$)

By dividing each implied probability by the overround sum, we normalize the values to equal exactly $100\%$, establishing the real-world probability distribution:

$$P'_A = \frac{P_A}{S}, \quad P'_B = \frac{P_B}{S}$$

Step 4: Convert Fair Probabilities Back into True American Odds

Once the fair probability ($P'$) is identified, we convert it back to standard American odds style without juice:

$$\text{True American Odds} = \begin{cases} -\left(\frac{P'}{1 - P'}\right) \times 100 & \text{if } P' > 0.5 \\ +\left(\frac{1 - P'}{P'}\right) \times 100 & \text{if } P' \le 0.5 \end{cases}$$

Practical Example: The Classic $-110$ Matchup

Consider a typical NFL or NBA point-spread bet where both options are priced at $-110$:

Implied Probabilities: Both $-110$ wagers imply a $\frac{110}{210} = 52.38\%$ likelihood of occurrence.
Total Overround: $52.38\% + 52.38\% = 104.76\%$
Fair Probabilities: Normalizing each side: $\frac{52.38\%}{1.0476} = 50.00\%$
True No-Vig Odds: Converting $50\%$ back into American formatting gives exactly $+100$ (Even Money).

House Edge vs. Overround (Vig)

Though often confused, "Vig" and "Overround" represent slightly different sides of the same coin:

Concept	Formula Definition	Core Meaning
Overround	$(S - 1) \times 100$	The percentage above 100% in sportsbook retail pricing lines.
Vigourish (Juice)	$\left(1 - \frac{1}{S}\right) \times 100$	The actual commission fee the house takes on total handle assuming balanced action.
True Odds	$\frac{1 - P'}{P'}$ (Ratio format)	The absolute baseline probability distribution with zero platform commission.

Why Professional Handlers Calculate Fair Value Odds