No-Vig Fair Odds: How to Strip Out the Sportsbook's Margin and Find the True Probability

What "No-Vig" Odds Actually Measure

Converting American Odds to Implied Probability

The first step is turning a price into a percentage. For negative odds, implied probability equals the odds' absolute value divided by that same value plus 100. A -150 favorite implies 150 ÷ 250, or 60%. For positive odds, implied probability equals 100 divided by the odds plus 100. A +130 underdog implies 100 ÷ 230, or about 43.5%. Calculated for both sides of a two-outcome market, these numbers always add up to more than 100% — and that extra percentage is the vig.

The Two-Way Devig Formula

Removing the vig is simple division once both implied probabilities are calculated: divide each side's implied probability by the sum of both. If Team A comes out to 60% and Team B to 43.5%, the total is 103.5%. Team A's no-vig probability is 60 ÷ 103.5, or about 58%; Team B's is 43.5 ÷ 103.5, or about 42%. Those two figures now sum to exactly 100%, representing the book's best estimate of each outcome's real chance with its margin removed.

A Worked Example With Real Numbers

Take a matchup priced at Team A -150 and Team B +130. Implied probabilities are 60% and 43.48%, summing to 103.48% — a 3.48-point overround. Dividing each side by that total gives no-vig figures of roughly 57.98% for Team A and 42.02% for Team B. Compare that to a pick'em game priced at -110 on both sides: each side implies 52.38%, the total is 104.76%, and the no-vig split comes back to an even 50/50. The size of the overround, not just the raw odds, shows how much margin is baked into a given line.

Why Three-Way and Multi-Outcome Markets Are Harder

Soccer moneylines, which include a draw, and markets with more than two outcomes — a golf tournament winner or an award race — follow the same principle but need every outcome's implied probability summed before dividing. A three-way soccer line with a home win, draw, and away win might total 106% instead of 100%, and each outcome gets divided by that 106% figure. The math scales cleanly to any number of outcomes; the only requirement is including every priced possibility in the sum, not just the two most likely results.

Where This Number Actually Gets Used

No-vig odds are the baseline sharp bettors and analysts use to judge whether a line is worth betting, because comparing a personal probability estimate against a book's raw price is misleading — the vig makes every raw price look worse than the book's true opinion. It is also the reference point behind closing line value: beating the closing no-vig number, not just the closing raw price, is what separates a genuine predictive edge from noise. Bettors tracking sharp money movement often watch how the no-vig split shifts between books rather than the raw odds themselves.

What Devigging Cannot Tell a Bettor

A no-vig number only reflects one book's opinion at one moment, dressed up as a cleaner percentage — it is not a guaranteed probability, and it does not account for a bettor's own information or model. Different sportsbooks devig to different numbers on the same game because they price margin differently, and comparing no-vig prices across several books is a better read on consensus than trusting any single line. The math removes the house's cut from the number; it does not remove the uncertainty of the underlying event.