Free betting calculator

Odds Converter

Convert any betting line between American, decimal and fractional formats, and reveal the implied win probability behind it.

Odds input format

Enter the odds (in the format selected above)

American

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Decimal

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Fractional

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Implied probability

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About odds formats

Sportsbooks show the same line in different formats by region. American odds use a plus or minus sign, decimal odds use a single multiplier, and fractional odds use a ratio. They all describe the identical wager. Pick your input format above, type the odds once, and every format plus the implied probability appears together.

Worked example

Take +150 in American odds.

To decimal: 150 ÷ 100 + 1 = 2.50.

To fractional: 2.50 − 1 = 1.5, written as 3/2.

Implied probability: 1 ÷ 2.50 = 0.40.

Result: +150 = 2.50 decimal = 3/2 fractional = a 40% implied win chance.

Frequently asked questions

What do American odds mean?

A positive number such as +150 is the profit on a $100 bet. A negative number such as -110 is how much you must stake to profit $100.

What is implied probability?

It is the win chance suggested by the odds. It includes the sportsbook's margin, so it reads slightly higher than an outcome's true probability.

Which odds format should I use?

Whichever you find clearest. Decimal makes payout math easy, American is standard in the US, and fractional is traditional in the UK — this tool speaks all three.