What implied probability is
It's the chance of an outcome, embedded in a market odd. Low odds imply high probability (favorite); high odds imply low probability (underdog).
Formula
Probability (%) = 100 ÷ decimal odds. And the reverse: decimal odds = 100 ÷ probability (%).
Why does a bookmaker's market add up to over 100%?
Because the odds offered embed the bookmaker's margin (the "vig" or "overround") — the sum of implied probabilities across all outcomes of a market is usually above 100%.
Frequently asked questions
Does a 50% implied probability guarantee a real 50% chance?
Not necessarily — it's just what the odds embed, which includes the bookmaker's margin. The "true" probability can differ.
Can I use this for any betting market?
Yes, the formula is the same regardless of sport or event, as long as the odds are in decimal format.
Does this apply to investing too?
A similar concept appears in options pricing and prediction markets, but this calculator is built for simple sports odds.