Odds Converter
Convert between decimal, American and fractional odds and see the implied probability. The break-even win rate the price demands.
Decimal
2
American
+100
Fractional
1/1
Implied probability
50.0%
Why implied probability is the number that matters
Every odds format is just packaging around one fact: the win rate you need to break even. Decimal 1.91 (American −110) demands 52.4%. If your true hit rate at those prices is 51%, you will lose money forever while feeling like a decent handicapper. That gap between felt performance and required performance is where most betting money dies: our guide to expected value walks through the math with real examples.
Whether you actually clear the bar isn't knowable from feel. Only from records. SmartBet Lab tracks your real hit rate against the prices you actually took, per league and market, from a one-click sync of your betting history.
Frequently asked questions
How do I convert American odds to decimal?
For positive American odds: decimal = 1 + (american ÷ 100), so +150 becomes 2.50. For negative: decimal = 1 + (100 ÷ |american|), so −200 becomes 1.50.
What is implied probability?
Implied probability = 1 ÷ decimal odds. Odds of 2.00 imply 50%, odds of 1.50 imply 66.7%. It is the break-even win rate the price demands. Beat it long-term and the bet is profitable.
Why do the implied probabilities in a market add up to more than 100%?
The excess is the bookmaker’s margin (vig/overround). A 1.91/1.91 two-way market implies 104.7%. That extra 4.7% is the house edge you must overcome.