No-Vig Odds Calculator
Strip the sportsbook's margin from any two-way market to see what the "fair" odds would be. Use to compare prices across books or against your own probability estimate for value-betting.
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The No-Vig Calculation
Posted odds at a sportsbook bake in the book's margin. To extract the "fair" no-vig price, we proportionally remove the margin from both sides:
- Convert posted odds on each side to implied probability
- Sum both probabilities (will exceed 100% by the hold)
- Divide each side's probability by the sum to renormalize to 100%
- Convert the normalized probabilities back to your preferred odds format
Example: a market priced -120 / +100. Side A implied prob = 120 / 220 = 54.55%. Side B implied prob = 100 / 200 = 50%. Sum = 104.55% (4.55% hold). Normalize: A = 54.55 / 104.55 = 52.18%, B = 50 / 104.55 = 47.82%. Convert back to American: A becomes -109, B becomes +109.
That -109 / +109 fair pair is the market's consensus probability with no margin : useful for comparing what different books actually believe before margin distortion.
Frequently Asked
What does "no-vig" mean?
No-vig (or "fair") odds strip the sportsbook's built-in margin from a market. They represent what the implied probabilities would be if the book took zero margin: the closest thing to the market's "true" assessment of each side. Useful for comparing posted odds at different books and identifying value bets.
How are no-vig odds calculated?
Convert each side's posted odds to implied probability, sum them (the sum will exceed 100% by the hold), then divide each side's probability by the sum to normalize back to 100%. The normalized probabilities are the "fair" probabilities; convert back to your preferred odds format to get the no-vig odds.
Why would I want no-vig odds?
Two main use cases: (1) Comparing the same market across multiple books to find the sharpest pricing — the book with the highest no-vig probability on a side believes most strongly in it. (2) Identifying value bets: if your model says a side has a 55% chance to win and the no-vig implied probability is 50%, you have a 5% edge.
How does this differ from the hold calculator?
Hold tells you the size of the sportsbook's margin. No-vig tells you what the odds would look like without that margin. Same input data, different output. Use hold when comparing margin across markets; use no-vig when comparing prices across books or against your own probability estimate.
Are no-vig odds the "true" odds?
No, they are the market's consensus estimate stripped of margin. The market is often right but not always: sharp bettors profit by finding markets where their own probability estimate differs meaningfully from the consensus. No-vig odds give you the consensus baseline to compare against.