Betting odds tell you two things: how much you can win and how likely the outcome is (according to the sportsbook).
The Three Major Formats
American
+150 / -200
Standard in North America. Based on $100.
Decimal
2.50
Global standard. Total return multiplier.
Fractional
3/2
Traditional UK. Profit ratio.
1. American Odds (+/-)
This format centers around the number $100.
- Negative (-): How much you must bet to win $100.
Example: -110 means bet $110 to win $100. - Positive (+): How much you win if you bet $100.
Example: +150 means bet $100 to win $150.
2. Implied Probability
Every set of odds can be converted into a percentage. This is called "Implied Probability." If you believe a team has a 60% chance to win, but the odds imply a 50% chance, that is a Value Bet.
| American | Decimal | Implied Prob | Meaning |
|---|---|---|---|
| -200 | 1.50 | 66.7% | Heavy Favorite |
| -110 | 1.91 | 52.4% | Standard Line |
| +100 | 2.00 | 50.0% | Even Money |
| +200 | 3.00 | 33.3% | Underdog |
Pro Tip: Removing the Vig
Notice that -110 implies 52.4%. If you bet both sides of a game at -110, the total probability is 104.8%. That extra 4.8% is the sportsbook's fee (the juice). To break even long term, you must win 52.4% of your bets, not 50%.