American odds explained clearly: what +200 and -150 mean, how to convert to probability, and how odds affect your hedging math.
American odds confuse a lot of newcomers. The plus/minus notation isn't intuitive at first glance — but it's actually pretty simple once you see the pattern. Here's the full breakdown, including how to convert odds to probability and why odds matter for hedging.
Negative odds (like -150, -300, -110) mean the team or outcome is a favorite — more likely than not to happen. The number tells you how much you need to bet to win $100.
In all cases, if you win, you get your original stake back plus the $100 profit.
Positive odds (like +150, +300, +110) mean the team or outcome is an underdog — less likely to happen. The number tells you how much you'd win on a $100 bet.
You don't have to bet exactly $100. These are just the reference point for the ratio. Bet $50 at +200 and you'd win $100.
Every set of odds implies a probability. Sportsbooks use this to represent how likely they think each outcome is.
For positive odds: Implied probability = 100 ÷ (odds + 100)
For negative odds: Implied probability = (-odds) ÷ (-odds + 100)
The key insight: for a 50/50 event, true even-money odds would be +100 (50% implied probability). But sportsbooks set both sides at -110 instead. This means both sides imply 52.4% probability — totaling 104.8%, not 100%. That extra 4.8% is the vig the sportsbook keeps.
Different sportsbooks price the same market differently. FanDuel might have Lakers at +150, DraftKings at +165. The game is the same. The probability estimate is (slightly) different.
These differences exist because each sportsbook manages their own risk, reacts to money flows differently, and has different customer bases that create different betting patterns.
For hedgers, this is the raw material. A 15-point difference in odds between two books on the same market can make the difference between a profitable hedge and not.
Game: Dallas Cowboys vs. New York Giants
| Moneyline | Spread | Total | |
|---|---|---|---|
| Cowboys | -165 | -3 (-110) | Over 44.5 (-110) |
| Giants | +140 | +3 (-110) | Under 44.5 (-110) |
Reading the Giants moneyline (+140): The Giants are underdogs. Bet $100 to win $140. Implied probability: 100 ÷ 240 = 41.7%.
Combined implied probability: 62.3% + 41.7% = 104%. The extra 4% is the sportsbook's vig margin.
For hedging with a bonus bet: The Giants +140 is the natural pick for a bonus bet — betting on an underdog with decent odds. At +140, a $200 bonus bet wins $280 in profit. You'd then hedge the Cowboys side with cash at another book.
Negative odds = favorite (you risk more to win $100). Positive odds = underdog (you win more than you risk). Implied probability converts odds to a percentage. The gap between different sportsbooks' odds on the same market is where hedging opportunity lives.
For the broader mechanics of how sportsbooks work, see our complete guide to how sports betting works.
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