Odds Converter
One American price in — decimal, fractional, and implied probability out.
Implied probability — how often a bet at −110 must win to break even.
Decimal odds — your total return per $1 staked, stake included.
Fractional odds — profit relative to stake, the way racebooks quote prices.
Worked example
A book lists a prop at +120. Decimal: 1 + 120/100 = 2.200, so a $10 stake returns $22.00 total. Fractional: 120/100 = 6/5 — win six for every five staked. Implied probability: 100 / (120 + 100) = 45.5%. If your fair read on the prop is better than a coin flip, that price has an edge; if it’s below 45.5%, walk away.
FAQ
What are American odds?
American odds quote prices relative to $100. A negative number like −110 is the amount you must stake to win $100; a positive number like +150 is the profit on a $100 stake. Favorites are negative, underdogs positive, and +100 is even money.
How do you convert American odds to decimal?
For positive odds, decimal = 1 + odds/100, so +150 becomes 2.50. For negative odds, decimal = 1 + 100/|odds|, so −150 becomes 1.667. Decimal odds multiply directly by your stake to give the total return, stake included.
What is implied probability?
Implied probability is the win rate at which a bet at that price breaks even. For negative odds it’s |odds| / (|odds| + 100), for positive odds it’s 100 / (odds + 100). −110 implies 52.38% — win more often than that and the bet is profitable.
Why does −110 show as 10/11 fractional?
Fractional odds quote profit relative to stake. Risking $110 to profit $100 reduces to the fraction 100/110 = 10/11. It’s the same price, written the way horse-racing books quote it.
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