No-Vig Fair Odds Calculator
Strip the bookmaker's margin to reveal true market probabilities and fair decimal odds.
| # | Market Odds | Fair Odds | True Probability |
|---|---|---|---|
| 1 | 2.10 | 2.105 | 47.50% |
| 2 | 1.90 | 1.905 | 52.50% |
Vig of 0.25%: The bookmaker takes this margin from every bet. Bet only when your estimated probability exceeds the fair probability shown above.
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Inputs locked
marketOdds
2.10, 1.90
Result snapshot
vig
0.25%
impliedSum
1.0025
fairOdds
2.105, 1.905
trueProbabilities
47.50%, 52.50%
18+ where legal. Educational calculator only. Bet sizing outputs are not financial advice.
How a No-Vig / No-Juice Calculator Works
Every sportsbook builds a margin — also called vig, juice, or overround — into their odds. This margin ensures the bookmaker profits regardless of the outcome. A standard 50/50 market (like a coin flip) might be offered at 1.91/1.91 instead of the true 2.00/2.00. That difference is the vig. This calculator removes it.
The implied probability of each side in a 1.91/1.91 market is 52.36% each — totaling 104.72%. The extra 4.72% is the bookmaker's overround. To find the true (no-vig) probability, we normalize: divide each implied probability by the total. The result: 50% each, with fair odds of 2.00/2.00.
For value bettors, this is mission-critical information. If you believe Team A wins 55% of the time, but the fair market probability is only 50%, you have a genuine edge. If the fair probability is 56%, you're actually betting into a loss. The no-vig odds reveal the market's true opinion — stripped of the bookie's cut.
Professional bettors use fair odds to benchmark their own models. If your probability estimate exceeds the fair implied probability, the bet has positive expected value. This calculator gives you the baseline you need to make that comparison on any market, regardless of format or number of outcomes.
The No-Vig Formula
Implied Sum = 1/Odds_1 + 1/Odds_2 + ... + 1/Odds_n Vig % = (Implied Sum − 1) × 100 Fair Prob_i = (1/Odds_i) / Implied Sum Fair Odds_i = 1 / Fair Prob_i
Works for any number of outcomes: 2-way (moneyline), 3-way (1X2), or multi-outcome markets. The more outcomes, the higher the vig typically is.
Devigging Methods: Multiplicative vs Additive vs Power
Removing the vig is not a single formula — there are several devigging methods, and they disagree most on lopsided markets. The three you will encounter most often:
Divide each implied probability by the implied sum. The margin is removed in proportion to each outcome's size. It is the industry-standard baseline and the method this calculator uses. Weakness: it ignores the favorite–longshot bias, so it tends to overstate a longshot's true chances.
Subtract an equal slice of the overround from every outcome (margin ÷ n). This assumes the book loads the same absolute margin on each side. It shifts more relative margin onto longshots than the multiplicative method, but it can produce negative probabilities on extreme outsiders — a sign it is being pushed beyond its range.
Raise each implied probability to a power k, then solve for the k that makes them sum to exactly 1 (found iteratively — there is no closed form). It concentrates the margin on longshots, which best matches how books actually price the favorite–longshot bias, and is popular for racing and outright markets.
For near-even two-way markets, all three methods give almost identical answers. They diverge on heavy favorites and longshots — precisely where mispricing your edge is most costly. Sharp bettors often compute two methods and treat the gap between them as an uncertainty band.
Take a hypothetical two-way market: favorite at 1.25, longshot at 4.20. Implied probabilities: 80.00% + 23.81% = 103.81%, so the vig is 3.81%. Each method removes it differently:
- Multiplicative: favorite 77.06% (fair odds 1.298), longshot 22.94% (fair odds 4.360).
- Additive: subtract 1.905 percentage points from each → favorite 78.10% (fair odds 1.280), longshot 21.90% (fair odds 4.565).
- Power (k ≈ 1.08): favorite ≈ 78.7% (fair odds ≈ 1.271), longshot ≈ 21.3% (fair odds ≈ 4.68).
The longshot's fair odds range from 4.36 to 4.68 depending on the method — a gap big enough to flip a marginal bet from +EV to −EV. When your edge is thin, check it against more than one devigging method before staking.
Real-World Examples
Liverpool 1.91 / Draw 3.50 (2-way, ignoring draw)
Implied: 52.36% + 28.57% = 80.9% (incomplete — add the draw for 3-way).
On a pure 2-way: 1.91/1.91 → implied sum 1.0472 → vig = 4.72%, fair odds 2.00 each.
Home 2.80 / Draw 3.20 / Away 2.40
Implied: 35.7% + 31.25% + 41.67% = 108.62% → vig = 8.62%.
Fair: Home 32.9%, Draw 28.8%, Away 38.4%.
Frequently Asked Questions
What is a fair vig percentage?
Typical sportsbooks charge 4–6% vig on popular markets. Sharp books like Pinnacle average 2–3%. Exchanges like Betfair charge 2–5% commission on winnings but otherwise operate near-zero vig.
How is no-vig different from implied probability?
Implied probability includes the bookmaker's margin. No-vig (or 'true') probability removes it. Always use no-vig probabilities when assessing whether your model has an edge over the market.
Can I use no-vig odds for arbitrage?
No — arbitrage requires finding odds across different bookmakers where the sum of implied probabilities is below 1.00. No-vig strips one book's margin and shows fair odds; it doesn't create arbitrage opportunities.
Why does vig vary by sport and market?
Bookmakers charge higher vig on niche markets where they have less certainty, to protect against sharp bettors. Major leagues and match results have lower vig; player props, lower leagues, and exotic markets carry more.
Which devigging method is most accurate?
It depends on the market. The multiplicative method is the standard baseline and works well for balanced two-way markets. The power method models the favorite–longshot bias best, so it is preferred for markets with big favorites, racing, and outrights. The additive method sits in between but can break down on extreme longshots. This calculator uses the multiplicative method.
What is the favorite–longshot bias?
A well-documented pattern where bookmakers (and bettors) systematically overprice longshots and underprice favorites relative to their true probabilities. Because of it, removing the vig proportionally overstates a longshot's true chance — which is exactly the problem power devigging tries to correct.