Work out odds to probability instantly with clear inputs, formula shown and shareable results.
Odds compare favourable to unfavourable outcomes, so odds of a to b mean probability a/(a + b). Decimal odds quote the total return per unit staked, which is the reciprocal of the probability.
Odds to probability
p = favourable / (favourable + against)
Decimal odds
decimal = 1 / p
3/10 = 0.3, that is 30%, with decimal odds of 3.333.
Because '3 to 1' means a probability of 0.25, not 0.33. Odds use a ratio of two counts, probability a fraction of the total.