The basic formula
For decimal odds, implied probability is p = 1 / odds. Odds of 2.00 imply 50%, 1.50 imply 66.67%, and 3.00 imply 33.33%.
The reverse calculation is equally simple: fair odds equal 1 / your probability. If your estimate is 40%, the margin-free reference price is 2.50.
Why the percentages add up to more than 100%
For mutually exclusive outcomes—home win, draw and away win, for example—add the implied probabilities. A bookmaker market normally totals more than 100%. The excess is the built-in market charge, or overround.
Odds of 2.00, 3.60 and 4.00 produce 50% + 27.78% + 25% = 102.78%. These are not fair probabilities until they have been normalised.
Market probability is not your probability
Implied probability describes the offered market price. Your probability is an independent estimate. The difference may indicate value only when your estimate is sufficiently accurate.
A few percentage points matter, especially at short odds. Record forecasts before kick-off and assess calibration over a large sample instead of remembering only successful picks.
How oddmind.app uses odds
oddmind.app first removes margin from market prices, then reconciles football markets through one score matrix. An official signal is locked before kick-off and added to the public record after settlement.
That makes the process verifiable, but it does not turn probability into a promise. Even a true 70% event fails roughly three times in ten over the long run.
Quick answers
Which decimal odds equal a 50% probability?
Decimal odds of 2.00, because 1 / 2.00 = 0.50.
Does a 70% probability mean the bet will win?
No. It estimates frequency across similar events, not the outcome of one event.
Can I compare my probability directly with the odds?
Yes, but a sound comparison must account for market margin and the quality of your estimate.
