No-Vig Calculator — Fair Odds & Devig Sports Betting
Remove the sportsbook vig from American odds to find true implied probability and fair odds for both sides of a two-way market.
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Full bio →American odds format: negative (e.g. -150) for favorites, positive (e.g. +130) for underdogs. Valid values are ≤ -100 or ≥ +100.
Implied probability (American odds): positive odds → 100 ÷ (odds + 100); negative odds → |odds| ÷ (|odds| + 100). The two sides' implied probabilities are summed (always over 100% — the excess is the vig), then each side's probability is divided by that sum to get the no-vig ("fair") probability, which is converted back to American odds. This uses the standard multiplicative devig method, most accurate for balanced two-way markets.
Reference Values
Last verified:| Category | Range | What It Means | Status |
|---|---|---|---|
| Standard Market (Low Vig) ★ | ~2–5% total vig | Typical for major sportsbooks on high-volume markets like NFL/NBA point spreads at -110/-110, which carries about 4.76% vig. | ★ Best |
| Moderate Vig | ~5–8% total vig | Common on moneylines with a clear favorite/underdog split, or slightly less liquid markets. | Good |
| High Vig | ~8–12%+ total vig | Common on player props, futures, and lower-liquidity markets where the book has less two-sided action to balance. | Okay |
| Extreme Vig | 12%+ total vig | Often seen on exotic or novelty markets — worth comparing against other books before betting, since the fair-odds gap is largest here. | Poor |
Source: Standard sports betting devig methodology (multiplicative proportional margin removal) applied to American odds implied probability
Worked Examples
Standard Spread Line: -110 / -110
- Side 1 Odds
- -110
- Side 2 Odds
- -110
Both sides have identical implied probability (52.38%), summing to 104.76% — the extra 4.76% is the vig. Removed, both sides are exactly even money (+100), confirming -110/-110 is a true coin-flip market before the book's cut.
Favorite/Underdog Line: -150 / +130
- Side 1 Odds
- -150 (favorite)
- Side 2 Odds
- +130 (underdog)
Raw implied probabilities are 60% and 43.48% (103.48% total). After removing the vig proportionally, fair odds shift to -138/+138 — the true edge is slightly smaller than the raw -150/+130 line suggested.
How to Use This Calculator
- 1
Enter the American odds for both sides of the market
Negative odds (e.g. -150) for favorites, positive odds (e.g. +130) for underdogs.
- 2
Read the total vig percentage
Shows exactly how much margin the book has built into this specific line.
- 3
Read the fair (no-vig) odds for each side
These represent the true, vig-free implied probability and equivalent American odds for each outcome.
What Each Value Means
- Implied Probability (percent (%))
- The probability of an outcome implied by a given set of odds, before removing the bookmaker's vig — always sums to over 100% across all outcomes of a market because it includes the book's built-in margin.
- Vig (Vigorish) (percent (%))
- The sportsbook's built-in profit margin, represented by the amount a market's total implied probability exceeds 100%. A -110/-110 line has 4.76% vig; higher-vig markets give the book a larger structural edge.
- No-Vig (Fair) Odds (American odds)
- Odds recalculated after proportionally removing the vig from both sides' implied probabilities, representing the market's true assessment of each outcome's likelihood with the book's margin stripped out.