Strip the vig, see fair odds.
Enter both sides of a two-way market and the calculator removes the sportsbook margin, returning the fair probability and fair odds for each side along with the hold the book is taking. It works the same on an NFL spread, an NBA total, or an MLB moneyline.
Fair. Side A
Fair. Side B
Market hold
Two prices in, fair probabilities out
Every two-sided sportsbook market carries a margin called the vig. Because of it, the implied probabilities of both sides add up to more than 100%. This calculator rescales the two so they sum to exactly 100%, leaving the fair probability each price implies once that margin is removed.
The steps are mechanical. Convert each side's American odds to an implied probability, add the two to get the overround, then divide each side by that total. The two results now sum to 100%. Convert each back to American odds and you have the fair, no-vig price. The gap between the raw total and 100% is the book's hold.
A concrete walk-through
Take an NFL total priced -120 on the over and +100 on the under. The over at -120 implies about 54.5%, and the under at +100 implies 50.0%. Added together that is 104.5%, so the extra 4.5 points are the margin rather than real probability.
To de-vig, divide each side by 104.5%. The over becomes roughly 52.2% and the under 47.8%, which now sum to 100%. Converting back to American odds, the fair prices land near -109 and +109, and the 4.5% hold is the difference between the raw market and a fair book. Those de-vigged probabilities give you a clean reference to compare against your own estimate or another book's line, whatever the sport.
No-vig odds, answered
What does 'no-vig' mean?
The vig, or juice, is the margin a sportsbook builds into its prices. Because of it, the implied probabilities of both sides of a market add up to more than 100%. Removing the vig (going 'no-vig') rescales those two numbers so they sum to exactly 100%, leaving the fair probability the price implies once the margin is taken out.
How do you calculate no-vig fair odds?
Convert each side's American odds to an implied probability, add the two together to get the overround, then divide each side's implied probability by that total. The results sum to 100% and are the fair probabilities; converting each back to American odds gives the fair, no-vig price. This calculator does all of that from the two prices you enter.
Why remove the vig at all?
A raw sportsbook price overstates how likely an outcome is, because it includes the book's built-in margin. Removing the vig gives you a cleaner read on the market's true probability estimate, which is a useful reference point to compare against your own number or another book's line.
What is a typical hold percentage?
The hold (shown here as market hold) is how much the two prices exceed a fair 100% between them. Tighter, more competitive two-way markets carry a smaller hold, while less liquid markets tend to carry a larger one. The calculator reports the exact figure for the two prices you enter rather than assuming a standard number.
Can I use no-vig odds as a probability estimate?
Yes. The de-vigged probability is a common way to turn a market price into a fair probability you can feed into an expected value or break-even calculation. It reflects the market's view with the margin stripped out, though it is still an estimate, not a certainty.
Does this work for both two-way and multi-way markets?
This calculator handles a standard two-way market, meaning two sides that between them cover every outcome, such as an NFL spread, an NBA moneyline, or any over/under. Multi-way markets with three or more outcomes use the same idea but sum more than two implied probabilities before rescaling.
De-vig every board, automatically
The calculator handles one market at a time. MySpariEdge compares prices across 25+ books and pick'em apps for you, surfacing where the market and the model disagree.