American Odds Explained; How to Read +150 and -180

The Two Rules

Rule 1: A minus number tells you how much you must risk to win $100. -180 means you risk $180 to win $100.

Rule 2: A plus number tells you how much you win if you risk $100. +150 means you risk $100 to win $150.

That's it. Every other American-odds calculation flows from these two rules.

Worked Examples

Let's convert real-world bets at typical Nevada lines.

• -110 (standard NFL spread): Risk $110 to win $100. Risk $11 to win $10. Total return on a $110 bet is $210 (your $110 stake + $100 profit).
• -180 favorite moneyline: Risk $180 to win $100. Risk $90 to win $50.
• +150 underdog moneyline: Risk $100 to win $150. Risk $20 to win $30.
• +400 longshot: Risk $100 to win $400. Risk $25 to win $100.
• -300 heavy favorite: Risk $300 to win $100. Risk $30 to win $10. Almost never worth it.

Implied Probability

Every odds line carries an implied probability; the win rate you'd need to break even.

• -110 → 52.4% (the standard NFL spread requires 52.4% wins to break even)
• -150 → 60.0%
• -200 → 66.7%
• +100 (even money) → 50.0%
• +150 → 40.0%
• +250 → 28.6%

The Vig (Juice)

Two-sided markets like spreads and totals usually price both sides at -110. If you add the implied probabilities; 52.4% + 52.4% = 104.8%; you get the sportsbook's built-in edge. That extra 4.8% is the vig (or juice). It's why you need to win more than 50% of your bets at -110 to profit; you need 52.4%.

Sharper books like Westgate offer reduced-juice markets like -105/-105 (102.4% total, only 2.4% vig). Over hundreds of bets that difference is enormous.

Decimal & Fractional Odds

Most Nevada apps let you switch the display. If American odds still feel unintuitive, try decimal format.

• Decimal odds show total return including stake; 2.10 means a $100 bet returns $210 (same as -110 American)
• Fractional odds (5/1) are common in horse racing; risk 1 to win 5
• American odds map to decimal: -110 = 1.91, +150 = 2.50