Implied Probability Explained
Implied probability is the win chance “baked into” betting odds. Once you can convert odds into probability, you can compare the book’s number to your own estimate and decide if a bet is worth it.
What is implied probability?
Implied probability is the percentage chance of an outcome that a set of odds represents.
Sportsbooks don’t post “Team A has a 52% chance.” They post odds. Your job is to translate odds back into a probability so you can think clearly.
Implied probability formulas
Decimal odds
Implied Probability = 1 / Decimal Odds
Example: 2.20 decimal odds → 1 / 2.20 = 0.4545 → 45.45%
American odds
For negative odds (e.g., -150):
Probability = |Odds| / (|Odds| + 100)
Example: -150 → 150 / (150+100) = 0.60 → 60%
For positive odds (e.g., +200):
Probability = 100 / (Odds + 100)
Example: +200 → 100 / (200+100) = 0.3333 → 33.33%
Quick conversion table (handy)
| Decimal | Implied % | American | Implied % |
|---|---|---|---|
| 1.50 | 66.67% | -200 | 66.67% |
| 1.80 | 55.56% | -125 | 55.56% |
| 2.00 | 50.00% | +100 | 50.00% |
| 2.50 | 40.00% | +150 | 40.00% |
| 3.00 | 33.33% | +200 | 33.33% |
Implied probability vs. “true” probability
The sportsbook’s implied probability isn’t the same as the real-world chance. Books add a margin (vig/juice).
If you convert both sides of a two-way market and the probabilities add up to more than 100%, that extra percentage is the bookmaker’s edge.
How to use implied probability to find value
- Convert the odds to implied probability.
- Make your own estimate of the true probability (model, research, or disciplined handicapping).
- If your true probability is higher than implied probability, that’s a positive expected value situation over time.
Next step: learn expected value (EV) and how it connects directly to probability.
FAQ
Why do implied probabilities add up to more than 100%?
Because sportsbooks build in a margin (vig/juice). The over-100% total represents the book’s edge on that market.
Is implied probability the same as chance to win?
It’s the chance represented by the posted odds, not necessarily the true chance in the real world.
Do I need implied probability to bet?
You can bet without it, but converting odds to probability helps you avoid emotional decisions and compare prices accurately.
Related next steps
- Gambling Glossary (quick definitions)
- Gambling Basics 101 (start here)
- Responsible Gambling (play safe)