American Odds

American odds (also called moneyline odds) express betting prices as positive or negative whole numbers anchored to a $100 unit. Negative odds denote the favourite and show the stake required to win $100 profit; positive odds denote the underdog and show the profit returned on a $100 stake. Worked examples: at -150 you must stake $150 to win $100 profit (a $250 total return). At +130 a $100 stake wins $130 profit ($230 returned). The unit is purely a reference point — the ratio scales, so -150 means risking $30 to win $20, or $15 to win $10. Converting to decimal odds: for negative prices, divide 100 by the absolute value and add 1. So -150 becomes 100/150 + 1 = 1.667. For positive prices, divide the number by 100 and add 1: +130 becomes 130/100 + 1 = 2.30. Converting to implied probability shows what the price assumes. A favourite of -150 implies 150 / (150 + 100) = 60%. An underdog of +200 implies 100 / (100 + 200) = 33.3%, and +130 implies 100 / (100 + 130) = 43.5%. These figures include the bookmaker's margin, so the two sides of a market sum to more than 100%. Why it matters: American odds are the default at US sportsbooks, so reading them fluently is essential for comparing prices and spotting value. The -100/+100 boundary marks an even-money bet. Common mistake: treating the $100 as a required stake. It is only a reference — you may wager any amount, and the payout scales proportionally to the quoted ratio. Compare to: Decimal Odds, Implied Probability, Moneyline.