American odds, sometimes called moneyline odds, represent prices using a plus or minus sign anchored to a value of 100. Negative odds apply to favourites and indicate the stake required to win 100 units of profit. Positive odds apply to underdogs and indicate the profit earned from a 100-unit stake. The original stake is returned on top in both cases.
For example, odds of -150 mean a bettor must stake £150 to win £100 in profit; a winning bet returns £250 in total. Odds of +200 mean a £100 stake wins £200 in profit, returning £300 in total. These figures scale proportionally, so at +200 a £25 bet wins £50 profit. Odds of -110, extremely common on point-spread and totals markets, mean staking 110 to win 100.
Converting to decimal odds clarifies the relationship. A -150 price equals 2.50 (150 ÷ 100, plus one, inverted appropriately gives 1.667) — more precisely, negative odds convert by dividing 100 by the number and adding one, so -150 becomes 1.667, while +200 becomes 3.00 by dividing the number by 100 and adding one.
A frequent misunderstanding is assuming the 100 is a fixed required stake. It is only a reference unit; any stake size works, and the proportions hold. Another is confusing the sign’s meaning: minus does not mean a bad bet, only that the selection is favoured and therefore pays less relative to the stake.
American odds are the standard across sportsbooks in the United States and in much of North American sports media. Bettors familiar with decimal or fractional formats often find the twin-number system initially awkward, particularly the switch in logic between favourites and underdogs. Because all odds formats describe identical prices, most online operators let customers display American, decimal or fractional odds interchangeably, which eases comparison for an increasingly international audience and for those following leagues outside their home region.