The method for finding arbitrage opportunities entails looking for significantly differing odds on the same sporting event. If the odds differ greatly enough, there is a reasonable chance for arbitrage. A betting calculator will tell you how much opportunity is available. It helps to look at some real-world examples.
To calculate your potential payout on an underdog, all you need to do is multiply your stakes (the amount of money you wagered) by the value resulting from the moneyline odds divided by 100. Put simply: Potential profit = Wager x (Odds/100).