If you've ever stared at "-110" and just tapped the button anyway, this one's for you. Odds tell you two things: how much you win and how likely the sportsbook thinks it is. Once that clicks, betting gets a lot less random.
American odds (+ and -)
- Minus (-150): how much you bet to win $100. Bet $150, win $100.
- Plus (+150): how much you win on a $100 bet. Bet $100, win $150.
Minus = favorite. Plus = underdog.
Decimal odds (2.50)
Common outside the US. It's your total return per $1, stake included. $10 at 2.50 returns $25, so $15 profit. Easy.
Turn odds into a probability
This is the move that changes everything. It's called implied probability.
- Minus odds: odds ÷ (odds + 100). -150 → 150 ÷ 250 = 60%
- Plus odds: 100 ÷ (odds + 100). +150 → 100 ÷ 250 = 40%
- Decimal odds: 1 ÷ odds. 2.50 → 40%
So a +150 bet only makes sense if you think it wins more than 40% of the time. If you think it's 35%, it's a bad bet, even if it hits tonight.
Why both sides add up to more than 100%
Look at a game where both sides are -110. Each side implies 52.4%. Together that's 104.8%. That extra ~4.8% is the vig, the book's cut. It's why you need to win more than half your -110 bets just to break even.
Quick cheat sheet
- -200 → 66.7%
- -110 → 52.4%
- +100 → 50%
- +200 → 33.3%
- +400 → 20%
The bottom line
Odds are just probabilities with a price tag. Turn every line into a %, compare it to what you really think, and only bet when your number beats the book's. That one habit already puts you ahead of most bettors.