Glossary / Prices & odds / Decimal odds
A ParlayAPI glossary entry

Decimal odds

Decimal odds are the European-standard format: the number is the total payout per unit staked, including the returned stake. A 2.30 decimal price pays $2.30 total per $1 bet ($1.30 profit). Implied probability is simply 1 divided by the decimal price.

In practice

# Decimal <-> American
        2.30   =  +130          # (decimal - 1) × 100 when ≥ 2.00
        1.667  =  -150          # -100 / (decimal - 1) when < 2.00
        # Parlay math is just multiplication in decimal:
        1.909 × 1.909 × 1.909 = 6.96

Decimal is the format of choice for computation: probabilities, parlays, and EV formulas all become one-liners, with no sign-flip special case.

Where it shows up in ParlayAPI

Request decimal prices via the odds-format parameter on any odds endpoint (the-odds-api-compatible). Exchange and international book prices are natively decimal, so cross-source comparison is cleanest in this format. Details in the docs.

Related terms

American oddsThe US-standard plus/minus odds format. Fractional oddsUK-style profit-per-stake fractions. Implied probabilityThe win probability an odds price implies. ParlayA multi-leg bet where every leg must win.