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Vig Calculator: Overround and No-Vig Odds
Enter every outcome of the same betting market. See implied probability, bookmaker overround and proportionally normalized no-vig odds. No actual win probabilities are predicted.
How it works & examplesUnderstand the calculation
Overround and a no-vig estimate are different results
The Vig calculator adds the implied probabilities of all entered prices. Two outcomes priced at 1.90 each imply about 52.63% each, for a total of 105.26%. The excess over 100%, about 5.26 percentage points, is the overround for that quoted market.
Once you remove the market margin, compare break-even probability and offered returns in Betting Odds Calculator: Decimal, Fractional, US.
Removing vig proportionally divides each implied probability by their total. It is a normalization method, not proof of the true chance of either outcome. Include every mutually exclusive result, including a draw when applicable. Mixing prices from different markets or omitting an outcome produces a sum that cannot be interpreted as that market's margin.
Maths & verification
Calculate overround from two-way or three-way decimal odds and remove the bookmaker margin proportionally. Transparent probability model.
Try the simulator below. Input values stay in your browser; no account or money is involved.
Model assumptions: No. Virtual games use declared teaching models. Verify any actual operator’s payout rules independently.
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How to use the tool
Measure the price margin built into a complete two- or three-outcome betting market.
- Collect decimal odds for every possible mutually exclusive result of one market.
- Choose two or three outcomes and enter the prices.
- Compare implied probabilities with normalized no-vig probabilities and odds.
Understanding your result
Bookmaker overround is (sum of 1/decimal odd − 1) × 100%. Removing it proportionally divides each implied chance by the sum. No-vig odds are the inverse of those adjusted probabilities.
Scope and limitations
No-vig odds are not known true probabilities. Incomplete markets, bet restrictions, rounding and unequal margin distribution change the interpretation.
Before you rely on the result
- How the calculation works
Formulas, assumptions, rounding and model limits are documented on the methodology page.
- Check the current inputs
Use the odds, RTP, fees, bonus terms or other values currently shown by the operator or market.
Vig and no-vig odds: overround, hold and fair probability
To measure bookmaker margin, convert every outcome in one complete market to implied probability and add them. A total above 100% is overround.
This calculator removes margin proportionally: no-vig probability for outcome i = raw implied probability i / total implied probability. That method is transparent but not the only possible de-vig model.
Example: −150 and +130
The favorite implies 60.00% and the underdog 43.48%, for a 103.48% probability total. Proportional normalization gives approximately 57.98% and 42.02%.
| Side | Book odds | Raw implied | Proportional no-vig |
|---|---|---|---|
| Favorite | −150 | 60.00% | 57.98% |
| Underdog | +130 | 43.48% | 42.02% |
Overround and hold are related but not identical
Overround is the excess implied-probability total: 103.48% − 100% = 3.48 percentage points. A hold-style margin expressed against the market total is 1 − 1/1.0348 ≈ 3.36%. State which definition you are using instead of treating the two numbers as interchangeable.
Why no-vig methods can disagree
Proportional, additive, power and Shin methods distribute the margin differently. This tool uses proportional normalization, so its fair probabilities should be interpreted as one transparent model rather than an objective forecast.
Price a market without bookmaker margin
Use this when
You have prices for every mutually exclusive outcome and want the market-implied fair probabilities.
Read the result like this
The no-vig probabilities should sum to about 100%; compare them with your own estimate rather than treating them as truth.
Common mistake
Removing vig does not predict the winner; it only normalizes the quoted market.
Worked example
For two outcomes both quoted at 1.90, each implies about 52.63%. The total is 105.26%, so overround is 5.26%. Proportional no-vig odds are 2.00 per side.
Does 2.00 mean each outcome is actually 50% likely?
No. It is a normalization of the supplied quotes and not an independent probability forecast.
Questions about this calculation
Does an overround of 5% mean a guaranteed 5% loss?
No. It is the difference between quoted implied probabilities and 100%; actual profit depends on which selections win.
What does a negative overround indicate?
An underround: the inverse-odds sum falls below one. Check the quotes and settlement terms before drawing conclusions.
When is Vig Calculator: Overround and No-Vig Odds the right tool?
Measure the price margin built into a complete two- or three-outcome betting market.
How should I read the result from Vig Calculator: Overround and No-Vig Odds?
Bookmaker overround is (sum of 1/decimal odd − 1) × 100%. Removing it proportionally divides each implied chance by the sum. No-vig odds are the inverse of those adjusted probabilities.
What can Vig Calculator: Overround and No-Vig Odds not tell me?
No-vig odds are not known true probabilities. Incomplete markets, bet restrictions, rounding and unequal margin distribution change the interpretation.