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.