Devig Calculator (Betting Odds)
What is Devigging?
Devigging (removing the vig/juice) converts sportsbook odds with built-in profit margin to true probabilities. Sportsbooks add “vig” (vigorish) to ensure profit regardless of outcome. For fair odds, total implied probability should equal 100%. When it exceeds 100%, the excess is the vig.
Devig Methods:
- Proportional: Most common. Reduces each probability proportionally.
- Multiplicative: Power method using square root of overround.
- Additive: Removes equal margin from all outcomes.
- Shin: Advanced method accounting for informed betting.
Example:
NFL Game: Team A -110, Team B -110
Implied: 52.38% + 52.38% = 104.76%
Vig: 4.76%
True Probabilities: 50% / 50%
Note: Devigging provides estimated true probabilities by removing bookmaker margins. Results vary by method. No method is definitively “correct” – each has theoretical justifications. Use devigged odds to identify value bets when your probability assessment exceeds the true probability. Always gamble responsibly.
Sports betting odds often include a hidden profit margin, known as the vig or juice, built in by sportsbooks. Understanding the true probability of outcomes is essential for identifying value bets and making informed decisions. The Devig Calculator simplifies this process by converting market odds with built-in margins into fair no-vig odds.
Whether you are betting on football, basketball, soccer, or any 2-way/3-way market, this tool calculates true probabilities and fair odds instantly. It supports multiple odds formats and devigging methods, making it a versatile resource for both beginners and professional bettors.
In this guide, we explain what devigging is, how to use the calculator step-by-step, provide examples, and share tips to maximize betting value.
What is Devigging?
Devigging is the process of removing the sportsbook’s vig/juice from the odds to find the true probabilities of outcomes. Sportsbooks ensure profit by building in this margin, so the total implied probability of all outcomes usually exceeds 100%.
For example, in a 2-way NFL game:
- Team A: -110
- Team B: -110
The implied probabilities are:
- 52.38% + 52.38% = 104.76%
- Vig/Margin = 4.76%
Devigging removes this excess margin to reveal true probabilities, often close to 50% for each team in this example.
How the Devig Calculator Works
The Devig Calculator works in three main steps:
- Input Odds: Enter the market odds in your preferred format: American, Decimal, or Implied Probability (%).
- Select Market Type: Choose 2-way (standard moneyline) or 3-way (moneyline with a draw).
- Choose Devig Method: Select a calculation method:
- Proportional (Most Common): Reduces each probability proportionally based on total implied probability.
- Multiplicative (Power Method): Adjusts probabilities using the square root of the overround.
- Additive (Margin Removal): Subtracts an equal portion of the vig from each outcome.
- Shin Method: Advanced technique accounting for informed betting patterns.
The calculator then provides:
- Total implied probability
- Sportsbook vig/margin
- Overround percentage
- True probabilities (no-vig)
- Fair odds in your selected format
- Verification (sum of true probabilities = 100%)
Step-by-Step Guide to Using the Devig Calculator
Step 1: Select Odds Format
Pick the format that matches your data:
- American Odds (e.g., -110, +150)
- Decimal Odds (e.g., 1.91, 2.50)
- Implied Probability (%) (e.g., 52.38%)
The input labels update automatically to guide you.
Step 2: Enter Market Odds
- Enter odds for Outcome A (Favorite) and Outcome B (Underdog).
- For 3-way markets, enable Outcome C (draw) and input the odds.
Step 3: Choose Market Type
- 2-way market: Standard head-to-head betting.
- 3-way market: Includes a draw (common in soccer).
Step 4: Select Devig Method
Pick one of the four methods depending on your preference or betting strategy. The Proportional method is widely used and provides accurate general results.
Step 5: Click Calculate
The calculator displays:
- Total Implied Probability: Sum of probabilities with vig
- Vig/Margin: Excess over 100%
- Overround: Relative percentage of total implied probability
- True Probabilities: No-vig probabilities for all outcomes
- Fair Odds: Adjusted odds for each outcome
- Verification: Confirms sum of probabilities = 100%
Example Usage
Example 1 – 2-Way Market (NFL Game):
- Team A: -110
- Team B: -110
- Format: American Odds
- Devig Method: Proportional
Output:
- Total Implied Probability: 104.76%
- Vig: 4.76%
- True Probabilities: 50% / 50%
- Fair Odds: -100 / -100
Example 2 – 3-Way Market (Soccer):
- Team A: 2.10
- Team B: 3.20
- Draw: 3.50
- Format: Decimal Odds
- Devig Method: Multiplicative
Output:
- Total Implied Probability: 108.33%
- Vig: 8.33%
- True Probabilities: 48.7% / 31.9% / 19.4%
- Fair Odds: 2.05 / 3.13 / 5.15
Tips for Using the Devig Calculator
- Always verify market odds format before inputting values.
- Use Proportional method for most accurate general use.
- For professional analysis, explore Shin method for informed betting scenarios.
- Use 3-way market feature for draws in soccer or other sports.
- Compare fair odds with your own probability estimates to identify value bets.
- Remember that no method guarantees profit; use responsibly.
Frequently Asked Questions (FAQs)
1. What is sportsbook vig?
Vig (vigorish) is the bookmaker’s built-in profit margin on odds.
2. Why do odds not sum to 100%?
Bookmakers include vig, causing the total implied probability to exceed 100%.
3. What is overround?
Overround is the percentage by which total implied probability exceeds 100%.
4. What is a 2-way market?
A market with two possible outcomes, e.g., head-to-head betting.
5. What is a 3-way market?
A market with three possible outcomes, usually including a draw.
6. How does the Proportional method work?
It reduces each outcome probability proportionally to remove vig.
7. How is the Multiplicative method different?
It uses the power method to adjust probabilities based on the square root of overround.
8. What is the Additive method?
It subtracts an equal portion of the vig from each outcome probability.
9. What is the Shin method?
An advanced technique accounting for informed betting on outcomes.
10. How do I read fair odds?
Fair odds are adjusted to represent no-vig market conditions.
11. Can I use this for soccer matches?
Yes, the calculator supports 3-way markets for draws.
12. Can I use implied probabilities directly?
Yes, input percentages directly in the “Implied Probability” format.
13. Does this guarantee winning bets?
No. It helps identify value but cannot predict outcomes.
14. Can I compare multiple sportsbooks?
Yes, by entering different odds from each sportsbook to find best value.
15. How does fair odds help bettors?
It reveals the “true” probability, allowing comparison with personal assessments to spot profitable bets.
Conclusion
The Devig Calculator is a powerful tool for anyone serious about betting analysis. By removing the bookmaker’s vig, it helps you understand the true probabilities, compare odds, and identify value betting opportunities. Whether for casual sports bettors or professional handicappers, this tool makes betting analysis transparent, fast, and easy.