Betting Odds Converter

All three odds formats encode the same thing — how much you profit relative to your stake if the bet wins — just written differently. Decimal odds are the simplest to compute from: they're the total payout multiplier including your stake, so profit ratio = decimal odds − 1, and the implied win probability is simply 1 ÷ decimal odds.

American (moneyline) odds use a sign convention: positive odds like +150 mean "a $100 bet profits $150" (profit ratio = odds ÷ 100), while negative odds like -200 mean "you must bet $200 to profit $100" (profit ratio = 100 ÷ |odds|). By convention, American odds are never quoted with a magnitude under 100 — that's the +100/-100 break-even boundary, which lines up exactly with decimal odds of 2.00 (even money).

Fractional odds write that same profit ratio directly as numerator/denominator (e.g. 3/2 means "profit 3 units for every 2 staked"). This calculator reduces the ratio to an exact fraction accurate to six decimal places rather than rounding to a 'nicer-looking' approximate fraction, so the result is always mathematically exact for the odds you entered.