Betting calculator
No-Vig Fair Odds Calculator
Remove bookmaker margin from a simple two-outcome market and estimate the no-vig fair probabilities and fair decimal odds.
Enter two decimal prices
Optional labels make the results easier to read.
| Outcome | Implied probability | No-vig fair probability | No-vig fair odds |
|---|---|---|---|
| Outcome A | 52.36% | 50.00% | 2.00 |
| Outcome B | 52.36% | 50.00% | 2.00 |
The margin is removed by scaling each implied probability by the total book percentage.
No-vig fair odds formula
The calculator first converts each price into implied probability, then divides each implied probability by the total book percentage.
Implied probability = 1 / decimal odds
Book percentage = implied probability A + implied probability B
Overround = book percentage - 1
Fair probability = implied probability / book percentage
Fair odds = 1 / fair probability
Worked example
If both outcomes are priced at 1.91, each side has an implied probability of about 52.36%. Together they add up to 104.71%, which is a 4.71% overround. After removing the margin, each side is estimated at 50.00%, which is fair odds of 2.00.
Responsible use
No-vig odds are an educational estimate. Real markets may include commission, void rules, liquidity, each-way terms, changing prices or other conditions. No-vig odds do not prove that a bet is good value and do not guarantee profit.
For the plain-English explanation behind the calculation, read What Are No-Vig Fair Odds?.