Welcome to our free Implied Probability Calculator at SportsBrackets.net! This interactive tool converts betting odds from American (moneyline), Decimal, or Fractional formats into the implied win probability percentage. It’s perfect for spotting value bets in events like Super Bowl LX props, March Madness moneylines, NHL playoffs, or any bracket-style tournament. Enter odds in any format. The calculator auto-converts the rest and shows the raw implied probability (including the bookmaker’s vig or overround).
Implied Probability Calculator
Implied Probability Calculator
American: —
Decimal: —
Fractional: —
Enter in any format — others update instantly. Raw implied % (includes vig).
How the Implied Probability Calculator Works
Here’s how the Implied probability calculator works. Implied probability is the bookmaker’s estimated chance of an outcome happening, derived directly from the odds. It often totals over 100% across all outcomes due to the sportsbook’s built-in margin (vig). Use this to compare against your own research-if your estimated probability is higher than the implied one (after accounting for vig), it could be a value bet.
Key formulas used in the calculator:
- American Odds (Moneyline):
- For negative odds (favorites, e.g., -110): Implied Probability = |odds| / (|odds| + 100) × 100
- For positive odds (underdogs, e.g., +200): Implied Probability = 100 / (odds + 100) × 100
- Decimal Odds (e.g., 1.91): Implied Probability = (1 / decimal odds) × 100
- Fractional Odds (e.g., 10/11): Implied Probability = denominator / (numerator + denominator) × 100
The tool handles conversions seamlessly and includes the vig in calculations. For a no-vig fair odds comparison, check out our Odds Converter tool (/odds-converter/) or average lines from multiple books.
Examples of Implied Probability in Action
Here are real-world examples tailored to popular sports and betting scenarios. These show how to use the calculator to evaluate props, moneylines, and totals-great for your Super Bowl squares, March Madness brackets, or NHL playoff picks.
Super Bowl LX Point Spread Example (Patriots vs. Seahawks)
Imagine betting on the spread or totals for the big game. Input these odds to see the implied probabilities:
| Bet Type | American Odds | Decimal Odds | Fractional Odds | Implied Probability |
| Patriots -4.5 | -110 | 1.91 | 10/11 | 52.38% |
| Seahawks +4.5 | -110 | 1.91 | 10/11 | 52.38% |
| Over 47.5 Points | -115 | 1.87 | 13/15 | 53.49% |
| Under 47.5 Points | -105 | 1.95 | 19/20 | 51.22% |
- Total Implied Probability: 52.38% + 52.38% = 104.76% (vig = 4.76% total, or ~2.38% per side). If your analysis gives the Patriots a 58% chance to cover, that’s a potential value bet on -110.
March Madness Moneyline Example (Hypothetical Final Four Matchup)
For underdog hunting in brackets, check moneylines like these:
| Team | American Odds | Decimal Odds | Fractional Odds | Implied Probability |
| Duke (Favorite) | -250 | 1.40 | 2/5 | 71.43% |
| Underdog Team | +200 | 3.00 | 2/1 | 33.33% |
- Total Implied Probability: 71.43% + 33.33% = 104.76% (vig = 4.76%). If you estimate the underdog has a 38% true win chance based on bracket trends, +200 could offer value.
NHL Playoff Underdog Example
Spotting edges in series prices during Stanley Cup playoffs:
| Scenario | American Odds | Decimal Odds | Fractional Odds | Implied Probability |
| Home Underdog vs. Favorite | +180 | 2.80 | 9/5 | 35.71% |
| Road Dog in Division Rivalry | +150 | 2.50 | 3/2 | 40.00% |
- If historical data shows home underdogs winning 38% of similar matchups, +180 might be a strong play.
Quick Reference Chart: Common Odds and Their Implied Probabilities
Use this table as a handy guide for break-even points in your betting strategy:
| American Odds | Decimal Odds | Fractional Odds | Implied Probability | Break-Even Bets (Wins Needed) |
| -500 | 1.20 | 1/5 | 83.33% | 5 out of 6 |
| -200 | 1.50 | 1/2 | 66.67% | 2 out of 3 |
| -150 | 1.67 | 2/3 | 60.00% | 3 out of 5 |
| -110 | 1.91 | 10/11 | 52.38% | 11 out of 21 |
| +100 | 2.00 | 1/1 | 50.00% | 1 out of 2 |
| +150 | 2.50 | 3/2 | 40.00% | 2 out of 5 |
| +200 | 3.00 | 2/1 | 33.33% | 1 out of 3 |
| +300 | 4.00 | 3/1 | 25.00% | 1 out of 4 |
| +500 | 6.00 | 5/1 | 16.67% | 1 out of 6 |
Tips for Using Implied Probability in Betting
- Find Value Bets: Compare the implied % to your own projections (from stats, brackets, or models). If yours is higher, bet. Accounting for vig (aim to beat it long-term).
- Shop Lines: Use odds from multiple sportsbooks; small differences in vig can add up.
- Common Mistakes to Avoid:
- Ignoring vig: Always calculate the overround.
- Over-relying on favorites: Underdogs often have inflated implied probs.
- Small-sample bias: Base estimates on data, not gut feelings.
- Tie into Brackets & Props: For Super Bowl squares or March Madness props, input odds for things like “first TD scorer” (+300 = 25%) and see if it aligns with your bracket predictions.
FAQs
- What is implied probability? It’s the win chance baked into the odds by the bookmaker.
- Why does the total exceed 100%? That’s the vig. The bookmakers’ profit margin.
- How do I calculate vig? Total implied probs minus 100%, divided by outcomes (e.g., 104.76% – 100% = 4.76% vig for a two-way bet).
- When is a bet valuable? If your estimated probability (e.g., 55%) > implied (e.g., 52.38%).
Ready to crunch some numbers? Try the calculator above and pair it with our Free Parlay Odds Calculator for multi-leg bets. Share your value finds in the comments or on X to @sportsbracketssol
