Like with other sports, sometimes you get a game where the favourite vs underdog split is just too wide to be good value, barring a miracle. But if you want to get in on the action despite that, and think there's a path to an edge, spread betting becomes one of your best football bets available. Here, the books set a line for what they expect the margin of victory to be, and you bet against that. In the above examples, a +6.5 spread means that the underdog will still pay out if they lose by six, though if the favourite wins by seven or more, the bet goes to them.