How do you convert American odds to decimal?

For a positive price, divide by 100 and add 1: +150 becomes 2.50. For a negative price, divide 100 by the absolute value and add 1: -110 becomes 1.909. Decimal odds include the stake, so 2.50 means $2.50 back for every $1 risked.

How do you convert decimal odds to American?

At 2.00 or above, subtract 1 and multiply by 100: 2.50 becomes +150. Below 2.00, divide -100 by the decimal minus 1: 1.909 becomes -110. Exactly 2.00 is +100, because an even-money underdog is conventionally written with a plus.

What is implied probability?

One divided by the decimal odds, expressed as a percentage. A price of -110 is 1.909 in decimal, so it implies 52.4%. That figure includes the sportsbook's margin, which is why both sides of a market add up to more than 100%.

Why does the converted American price get rounded?

Sportsbooks post whole numbers. A decimal of 1.913 converts to -114.7, which no book would ever show, so the result is rounded toward zero to the nearest price that could actually be posted. The decimal and probability figures are left exact.

Free calculator

Odds Converter

Convert American odds to decimal odds and implied probability, in any direction, and see what each price returns on a $100 stake.

Convert from

American odds

e.g. -110 or +150

Equivalent

American: -110
Decimal: 1.909
Implied probability: 52.38%
Profit on $100: $90.91
Returns on $100: $190.91

A converted American price is rounded to a whole number, because that is the only thing a sportsbook posts. The decimal and probability figures are exact.

Frequently asked questions

How do you convert American odds to decimal?: For a positive price, divide by 100 and add 1: +150 becomes 2.50. For a negative price, divide 100 by the absolute value and add 1: -110 becomes 1.909. Decimal odds include the stake, so 2.50 means $2.50 back for every $1 risked.
How do you convert decimal odds to American?: At 2.00 or above, subtract 1 and multiply by 100: 2.50 becomes +150. Below 2.00, divide -100 by the decimal minus 1: 1.909 becomes -110. Exactly 2.00 is +100, because an even-money underdog is conventionally written with a plus.
What is implied probability?: One divided by the decimal odds, expressed as a percentage. A price of -110 is 1.909 in decimal, so it implies 52.4%. That figure includes the sportsbook's margin, which is why both sides of a market add up to more than 100%.
Why does the converted American price get rounded?: Sportsbooks post whole numbers. A decimal of 1.913 converts to -114.7, which no book would ever show, so the result is rounded toward zero to the nearest price that could actually be posted. The decimal and probability figures are left exact.

The three formats, and what each one says

A price can be written three ways, and all three carry the same information in different units. Which one is easier depends entirely on the question you are asking.

American odds answer “what does this pay?” A positive number is the profit on a $100 stake; a negative number is the stake needed to profit $100. It is the format every US sportsbook posts.
Decimal odds answer “what comes back?” Multiply the stake by the decimal and you have the total return, stake included. This is the only format the arithmetic works in, which is why parlay maths converts to it first.
Implied probability answers “how often does this have to win?” It is the price restated as a percentage, and it is the version worth comparing against your own opinion of the game.

The conversions

American	Decimal	Implied probability	Profit on $100
-250	1.400	71.43%	$40.00
-110	1.909	52.38%	$90.91
+100	2.000	50.00%	$100.00
+150	2.500	40.00%	$150.00
+400	5.000	20.00%	$400.00

Why both sides add up to more than 100%

Two sides of a market at -110 imply 52.38% each, which totals 104.76%. The extra 4.76 points are the sportsbook's margin — the vig — and they are the reason a bettor who wins exactly half their -110 bets loses money over time. The implied probability calculator removes it and reports what each side's fair price would be.