Understanding American Odds: A Complete Guide

American odds (also called moneyline odds) are the standard format used by sportsbooks in the United States. They're displayed as either positive (+) or negative (-) numbers and tell you how much you'll win relative to a $100 bet. While they may seem confusing at first, American odds become intuitive once you understand the basic principles.

Positive Odds (+) - The Underdog

Positive odds show how much profit you'd make on a $100 bet. The number represents your potential profit, not your total return.

Examples:
+150 odds: Bet $100 to win $150 profit (total return $250)
+300 odds: Bet $100 to win $300 profit (total return $400)
+500 odds: Bet $100 to win $500 profit (total return $600)

You don't have to bet exactly $100. A $50 bet at +150 wins $75. A $200 bet at +300 wins $600. The formula: (Stake × Odds) / 100 = Profit

Negative Odds (-) - The Favorite

Negative odds show how much you need to bet to win $100 profit. The number represents the required stake for $100 profit.

Examples:
-150 odds: Bet $150 to win $100 profit (total return $250)
-200 odds: Bet $200 to win $100 profit (total return $300)
-500 odds: Bet $500 to win $100 profit (total return $600)

For other bet amounts: (Stake × 100) / Odds = Profit
A $300 bet at -150 wins $200. A $100 bet at -200 wins $50.

Implied Probability

Every odds line contains an implied probability - the likelihood of the outcome according to the oddsmaker (including vig).

Calculating Implied Probability:

For Positive Odds: 100 / (Odds + 100)
+150: 100 / (150 + 100) = 40% implied probability

For Negative Odds: Odds / (Odds + 100)
-150: 150 / (150 + 100) = 60% implied probability

Understanding implied probability helps you identify value. If you believe the true probability is higher than implied, the bet has positive expected value.

Common Odds Meanings

Certain odds appear frequently and have specific implications:

• -110: Standard point spread or totals odds (bet $110 to win $100). Implies 52.4% probability
• +100 (Even money): Bet $100 to win $100. Exactly 50% implied probability
• -200: Heavy favorite, often seen in mismatch games. Implies 66.7% probability
• +300: Significant underdog. Implies 25% probability
• +1000: Long shot bet. Implies 9.1% probability

Pro Tips for Reading American Odds

Remember: the bigger the negative number, the bigger the favorite (and the more you must risk). The bigger the positive number, the bigger the underdog (and the more you can win). When comparing odds across books, even small differences matter - shopping -105 vs -110 saves you money over time. Use our Odds Converter tool to quickly convert between American, decimal, and fractional formats and see implied probabilities instantly.