Convert any price between American, decimal and fractional, read the win chance it implies, and check whether it beats your own estimate.
American
-110
Decimal
1.909
Fractional
10/11
Implied chance
52.38%
Value per $1
+5.00%
Kelly stake
$55.00
Reading a price
A minus price is what you risk to win $100: -110 risks $110 for $100. A plus price is what $100 wins: +150 wins $150. Decimal odds fold the stake back in, so 2.50 returns $2.50 for every $1 including the stake.
Implied chance is simply 1 ÷ decimal. Two sides of the same market always add up to more than 100% — that gap is the sportsbook's margin, which is why shopping the best price matters more than picking winners.