American odds
The US sportsbook price format: negative numbers show the risk to win $100, positive numbers show the win on a $100 risk.
−110 means risk $110 to win $100 (decimal 1.909, implied 52.4%). +250 means risk $100 to win $250 (decimal 3.50, implied 28.6%). The format hides the margin well, which is why comparing books is easier in decimal or probability terms.
ArbMonster displays sportsbook legs in American odds by default with a sidebar toggle to decimal, and every calculation underneath runs on implied probabilities.
Measured on ArbMonster: Odds converter
Related terms: Decimal odds · Implied probability · Moneyline