American Odds to Probability Odds Converter
How to convert American odds to Probability odds
Use this calculator to convert American odds into implied probability. Enter a valid value and the converter will instantly return the equivalent implied probability value.
How American odds are converted to implied probability
The simplest method is to convert American odds into decimal odds first, then convert the decimal odds into implied probability. This reduces sign errors and keeps the calculation consistent across different betting formats.
For example, American odds of +150 convert to implied probability of 40%.
Worked example
Convert American odds of -120 to implied probability
Since -120 is negative, use the formula |American odds| / (|American odds| + 100).
120 / (120 + 100) = 0.5455.
Convert that decimal into a percentage.
The implied probability is 54.55%.
Important note for this conversion
Whenever implied probability is involved, the conversion is useful for comparing bookmaker prices with your own estimated win chance or model projection.
Common conversion mistake
A common mistake with American odds is forgetting that positive and negative values use different formulas. Always check the sign before converting.
American odds explained
The sign is the key to reading American odds. Positive prices indicate underdogs and larger returns per 100 staked, while negative prices indicate favourites and a larger required stake to win 100. Once converted, they map cleanly to decimal and implied probability.
Probability odds explained
Implied probability shows the chance suggested by the quoted odds before adjusting for bookmaker margin. It is useful for evaluating bet value, comparing market prices, and understanding how aggressive or conservative a sportsbook’s pricing really is.
Supported odds formats
In addition to converting American odds into implied probability, the underlying calculator supports the main odds formats used worldwide. This includes decimal, fractional, American, Hong Kong, Malaysian, Indonesian, and probability-based pricing.
Why use an odds converter?
A American odds to implied probability conversion is useful when researching bets across multiple regions or bookmakers. Instead of mentally translating between formats, you can compare the same price in a form that is easier for you to understand.
Frequently asked questions
What is the easiest way to convert American odds to implied probability?
In most cases, the easiest method is to convert American odds into decimal odds first and then convert the decimal odds into implied probability.
Why do bettors convert American odds into implied probability?
Bettors often convert American odds into implied probability to compare bookmaker prices more easily, understand implied probability, and read markets in the format they are most comfortable with.
Can I compare bookmakers more easily after converting American odds to implied probability?
Yes. Once both prices are in the same format, it becomes much easier to spot value differences, compare payout levels, and evaluate whether one bookmaker is offering a better line than another.
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