No Vig Fair Odds Calculator

There are several methods for vig removal, but we'll discuss one that removes vig proportionally based on the odds. This is sometimes called the Margin Proportional to Odds (MPTO) method, and works fine in most cases. For removing vig from markets with large favorites or multi-ways (3 or more sides), the Power method can be a better choice. Let's work through each step of the MPTO method, which is what the no vig fair odds calculator uses.

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Step 1: Convert American odds to probability

If the odds are positive, use the equation:

Probability = 100 / (Odds + 100)

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If the odds are negative, use the equation:

Probability = |Odds| / (|Odds| + 100)

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Note: You can also use the betting odds calculator to convert between odds formats.

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Step 2: Add the probabilities together

Total Probability = Probability 1 + Probability 2

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Step 3: Divide each side by total probability

No Vig fair probability 1 = Probability 1 / Total Probability
No Vig fair probability 2 = Probability 2 / Total Probability

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Now they add up to exactly 100%.

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Step 4: Convert probabilities back to American odds

If the probability is >0.5:

Fair Odds = -(Probability / (1 - Probability)) * 100

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If the probability is 0.5 or less:

Fair Odds = ((1 - Probability) / Probability) * 100

After converting back to American odds, they're easier to compare to the sportsbook's price.

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Example

A sportsbook's odds for two teams are:

• Team A: -120

• Team B: +100

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Step 1: Convert both sides to probability

For Team A (-120):

120 / (120 + 100) = 0.5455 = 54.55%

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For Team B (+100):

100 / (100 + 100) = 0.5000 = 50.00%

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Step 2: Add the probabilities together

54.55% + 50.00% = 104.55%

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That total is above 100% because of the vig.

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Step 3: Divide each side by total probability

For Team A:

54.55 / 104.55 = 52.18%

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For Team B:

50.00 / 104.55 = 47.82%

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Now the probabilities add up to 100 percent, so we've successfully removed the vig.

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Step 4: Convert probabilities back to American odds

For Team A at 52.18%:

Fair Odds = -(0.5218 / 0.4782) * 100 = -109

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For Team B at 47.82%:

Fair Odds = (0.5218 / 0.4782) * 100 = +109​​

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That means the sportsbook’s listed market of -120 / +100 becomes a fair market of about -109 / +109 after removing the vig. This is an estimate of the "true" market price instead of the sportsbook’s marked up price.