Odds Converter
Convert between American, decimal, fractional odds and implied probability. Type in any one field and the other three update instantly.
The four odds formats
- American / moneyline — used in the US. A positive number (
+150) is the profit on a $100 stake; a negative number (-150) is the stake needed to win $100. - Decimal — used in Europe and Australia. The total return per $1 staked, stake included.
2.50returns $2.50 for every $1. - Fractional — used in the UK. Profit relative to stake:
3/1("three to one") pays $3 profit per $1. - Implied probability — the win chance the price bakes in, including the book's margin. It's
1 ÷ decimal odds.
Why the implied probabilities add up to more than 100%
Add the implied probabilities of both sides of a market and you'll get more than 100% — the extra is the book's hold. Strip it out with the no-vig calculator to see the true probabilities.
Stop doing this by hand
These calculators do one bet at a time. PropPrizm's EV+ board runs the de-vig and EV math across every book, on every prop, live — and surfaces only the ones where a book is soft versus the market consensus.
See the EV+ board →Frequently asked questions
How do you convert American odds to decimal?
For positive odds: decimal = 1 + (American / 100). For negative odds: decimal = 1 + (100 / |American|). Example: +150 → 2.50; -150 → 1.667.
What does implied probability mean?
It is the win probability the odds imply, equal to 1 divided by the decimal odds. Note it includes the book’s margin, so the two sides of a market sum to more than 100%.
What is the decimal equivalent of -110?
-110 in American odds equals 1.909 in decimal, 10/11 fractional, and about 52.4% implied probability.