Plus and minus, in one sentence each
- A plus price is the profit on a $100 bet: +150 wins $150.
- A minus price is what you bet to win $100: −200 means betting $200 to win $100.
The minus side is the favorite, the plus side the underdog. A price of +100 is an even-money bet: $100 wins $100.
What $100 pays
- $100 at +150 returns $250: your $100 back plus $150 profit (decimal 2.50).
- $100 at −200 returns $150: your $100 back plus $50 profit (decimal 1.50).
Decimal odds, used in most of the world, are the same thing written as the total return per $1 staked, stake included.
Turning a price into a chance to win
Every price implies how often the bet has to win just to break even. The formulas:
- Plus price: 100 ÷ (price + 100).
- Minus price: price ÷ (price + 100), ignoring the minus sign.
- +150 implies a 40.0% chance: 100 ÷ 250.
- −200 implies a 66.7% chance: 200 ÷ 300.
- −110 implies a 52.4% chance: 110 ÷ 210.
If you think a team wins more often than its price implies, the price is generous by your numbers. If less often, it isn't. That is the whole of judging a price.
Why −110 on both sides isn't 50/50
A game priced −110 on both teams is a coin flip, yet each side implies 52.4%. The two add up to 104.8%, not 100%. The extra is the book's margin, the vig: it is how the book gets paid whichever side wins.
So a price's implied chance always overstates the real one a little. Taking the margin out gives the fair, or no-vig, chance, which is the number CacheOut's calls start from. The no-vig guide shows how.
Not betting advice. 21+ where permitted.