Type a price in any format and get the other two, plus the chance the price implies and what it pays on a tenner. Useful when one book prices in fractions and another in American.
All three formats describe the same thing. Decimal (2.75) is your total return per $1 staked, stake included. Fractional (7/4) is profit against stake — $7 back for every $4 risked. American shows the profit on a 100 stake for positive prices (+175) or the stake needed to win 100 for negatives (−150).
To convert fractional to decimal, divide the fraction and add one: 7/4 is 1.75, plus one is 2.75. For American, a positive price is (odds ÷ 100) + 1, and a negative is (100 ÷ odds) + 1. The converter handles all of this instantly, so you can compare a fractional price at one book with an American price at another.
Divide one by the decimal price for the implied probability — the chance the price assumes. 1 ÷ 2.75 is 36.4%. Add up the implied chances of every runner in a market and the total comes to more than 100%; that surplus is the bookmaker's margin, the overround, and beating it is the whole game.