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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.

Updated

American odds format: negative (e.g. -150) for favorites, positive (e.g. +130) for underdogs. Valid values are ≤ -100 or ≥ +100.

Total Vig (Bookmaker Margin)
4.76%
Fair Odds — Side 1
+100
50.00% true probability
Fair Odds — Side 2
+100
50.00% true probability

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.
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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
Total vig: 4.76% · Fair odds: +100 / +100

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)
Total vig: 3.48% · Fair odds: -138 / +138

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. 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. 2

    Read the total vig percentage

    Shows exactly how much margin the book has built into this specific line.

  3. 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.

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Frequently Asked Questions

How do you calculate implied probability from American odds?
For positive odds: Implied Probability = 100 ÷ (Odds + 100). For negative odds: Implied Probability = |Odds| ÷ (|Odds| + 100). For example, -110 odds imply 110 ÷ 210 = 52.38% probability, and +130 odds imply 100 ÷ 230 = 43.48% probability.
What is vig (or juice) in sports betting?
Vig (short for vigorish, also called juice) is the sportsbook's built-in margin — the reason both sides of a two-way market's implied probabilities always sum to more than 100%. A standard -110/-110 spread line has implied probabilities of 52.38% each, totaling 104.76% — the extra 4.76% is the vig, representing the book's expected profit margin regardless of outcome.
How do you remove the vig to find fair odds?
Divide each side's implied probability by the total combined implied probability (which is always over 100%), then convert the resulting 'no-vig' probability back to American odds. For a -110/-110 line: both sides' 52.38% implied probability, divided by the 104.76% total, gives exactly 50% each — converting back to American odds gives +100/+100 (even money), confirming that market has no inherent edge before the vig.
Why does removing the vig matter for bettors?
Fair (no-vig) odds represent the market's true assessment of each outcome's probability, stripped of the book's margin. Comparing a specific sportsbook's posted odds against the no-vig fair odds shows exactly how much edge you're giving up by betting there — useful for finding value, comparing multiple books, or building your own probability models independent of any single book's line.
What devig method does this calculator use?
This calculator uses the multiplicative method — proportionally dividing each side's implied probability by the total to remove the vig. It's the most common and simplest devig method, and works well for balanced two-way markets. More advanced methods (Shin, power) exist and can be more accurate for markets with extreme favorites, but multiplicative is the standard starting point and is what most public no-vig tools use by default.

References & Sources

  1. [1]
    Journal of Quantitative Analysis in Sports — Odds-Implied Probability (opens in new tab)

    Supports: Academic treatment of odds-implied probabilities, bookmaker overround, and multiplicative normalization.

    Verified

  2. [2]
    National Council on Problem Gambling (opens in new tab)

    Supports: Independent responsible-gambling information, help resources, and risk context for betting tools.

    Verified

  3. [3]
    NIH PubMed Central — Sports Gambling and Decision Errors (opens in new tab)

    Supports: Peer-reviewed formulas for implied probability and bookmaker profit margin, plus gambling-risk evidence.

    Verified