Moneyline odds are favoured by American bookmakers.
If the figure quoted is negative, then the moneyline odds are quoting how much money must be wagered to win $100 – this is done if the odds are worse than even.
If the figure quoted is positive, the odds are quoting how much money will be won on a $100 wager – this is done if the odds are better than even.
Even odds can either be quoted as $100 or -$100. Fractional odds of 4/1 would be quoted as (+)$400, while fractional odds of 1/4 would be quoted as -$400.
Moneyline odds are often referred to as American odds. Moneyline refers to odds on the straight-up outcome of a game with no consideration to a point spread.