A spread of +3.5 means a team must win outright or lose by fewer than four points to cover the spread. A +3.5 spread is particularly enticing in football because, as noted earlier, 3-point victory margins are extremely common. An example of a +3.5 spread: New England Patriots +3.5. Miami Dolphins -3.5.
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).