What is implied probability?
Implied probability translates betting odds into percentages — the “implied” chance of an outcome happening based on the bookmaker’s prices.
For example, decimal odds of 2.00 equal an implied probability of 50%. That means, according to the market, your bet has a one-in-two chance of landing.
Understanding how odds convert to probability
Every odds format — decimal, fractional, or American — expresses probability in a different way. Converting them gives you a clear, apples-to-apples comparison.
| Odds format | Example | Formula | Implied probability |
| Decimal | 2.00 | 1 / 2.00 | 50% |
| Fractional | 1/1 | 1 / (1 + 1) | 50% |
| American (+100) | 100 / (100 + 100) | 50% |
Once you express odds as percentages, it’s easier to assess fair value — or spot when the sportsbook might have mispriced a market.
Examples: -110, +150, 200, -250
Win %: —
How we calculate
American: If odds are −X, p = X / (X + 100). If +X, p = 100 / (X + 100). ×100 for %.
Decimal: p = (1 / Decimal Odds) × 100.
Fractional (n/d): p = d / (n + d) × 100.
For information purposes only. Please gamble responsibly.
