How betting odds work
Betting odds tell you two things: how much a bet pays and the chance the book is giving it. The same odds can be written three ways. American odds use plus and minus (a -110 favorite, a +150 underdog). Decimal odds show the total return per $1 staked (1.91). Fractional odds show profit to stake (10/11). They are the same number in different clothes, and this converter turns any one into the others instantly, then shows your payout.
What do + and - mean in betting odds?
A minus number like -110 is the favorite: it is how much you must stake to win $100. A plus number like +150 is the underdog: it is how much you win on a $100 stake. The bigger the minus, the bigger the favorite. The bigger the plus, the bigger the underdog and the payout.
How to read and convert odds
- American to decimal: for a plus price, decimal = 1 + (odds / 100). For a minus price, decimal = 1 + (100 / odds).
- Decimal to American: if decimal is 2.00 or higher, American = (decimal - 1) x 100. If lower, American = -100 / (decimal - 1).
- Fractional to decimal: decimal = 1 + (numerator / denominator). 10/11 = 1.91.
- Implied probability: implied % = 100 / decimal odds. So -110 implies about 52.4%.
What is implied probability?
Implied probability is the win rate the odds price in, which is also your break-even rate. At -110 you need to win about 52.4% just to break even. Here is the catch: a book's two sides add up to more than 100%, and that extra is the vig (their margin). So the true no-vig fair probability is lower than the implied number. Finding bets where your real chance beats the implied price is the entire edge, and it is what our line shopping and +EV tools do automatically.
The Wise Guy Team way
Convert to whatever format you think in, but never bet a number without checking it against the field. The best price across regulated US books, and the no-vig fair line behind it, is where the money is.
Frequently asked questions
How do betting odds work?
Odds show both the payout and the implied chance of a bet. American odds use plus and minus, decimal odds show return per $1, and fractional odds show profit to stake. They all describe the same price.
What do + and - mean in betting odds?
Minus is the favorite (stake that much to win $100); plus is the underdog (win that much on a $100 stake).
How do you convert American odds to decimal?
For a plus price, decimal = 1 + odds/100. For a minus price, decimal = 1 + 100/odds. Example: -110 becomes 1.91, +150 becomes 2.50.
What is implied probability?
It is the win rate the odds price in and your break-even rate. Implied % = 100 / decimal odds, so -110 implies about 52.4%.
How do you calculate payout from odds?
Multiply your stake by the decimal odds for the total payout, then subtract the stake for profit. This tool does it as you type.
Which odds format is best?
They are identical in value, so use whatever you read fastest. Sharp bettors often use decimal because it makes comparing prices and computing payouts easy.
21+. For entertainment and educational purposes, not financial advice. If gambling stops being fun, take a break. 1-800-GAMBLER.