Reading odds: −110 and +130
Odds do two jobs at once. They tell you what a winning bet pays, and they quietly tell you how often the bet has to win to be worth making. Read both and every price on the board starts to make sense.
American odds in one rule
US sportsbooks show American odds, built around $100:
- Minus odds (−150) say how much you risk to win $100. Risk $150, win $100.
- Plus odds (+130) say how much you win when you risk $100. Risk $100, win $130.
On a moneyline, minus marks the favorite and plus marks the underdog. You don't have to bet $100; the ratio scales. At −150 a $30 bet wins $20, and at +130 a $20 bet wins $26. When you win, your stake comes back too.
The price you'll see most is −110, the standard on spreads and over/unders: risk $110 to win $100, or $11 to win $10.
From odds to a percentage
Every price implies a chance, called its implied probability. Two formulas cover it:
- Minus odds: risk ÷ (risk + 100). For −110 that is 110 ÷ 210 = 52.4%.
- Plus odds: 100 ÷ (odds + 100). For +130 that is 100 ÷ 230 = 43.5%.
The most useful way to read that number is as your break-even rate: the share of these bets you must win just to not lose money. At −110 you need to win 52.4% of the time. Win 50%, like a coin flip, and you slowly lose. At +130 you need only 43.5%, because each win pays more.
That changes the question you ask. It is never just "will this team win?" It is "will this team win more often than the price needs?" A −300 favorite that wins 70% of the time is a losing bet, because −300 needs 75%. An underdog at +200 that wins 36% of the time is a good one, because +200 needs only 33.3%.
Add both sides' implied chances in one game and you'll get more than 100%. That extra is the bookmaker's fee, the subject of the next lesson.
An aside: decimal odds
Much of the world uses decimal odds, and the American/Decimal switch above the board shows them too. A decimal price is your full return per $1, stake included: 2.30 returns $2.30 on $1, a $1.30 profit, the same price as +130. −110 is 1.91 and −150 is 1.67. Break-even is 1 ÷ the decimal: 1 ÷ 1.91 = 52.4%. Same price, different notation.
Example. A game priced Bears −150, Lions +130 (illustrative prices, not live data):
| Bears −150 | Lions +130 | |
|---|---|---|
| You risk | $150 | $100 |
| Profit if it wins | $100 | $130 |
| Paid back if it wins | $250 | $230 |
| Break-even rate | 60.0% | 43.5% |
| Decimal odds | 1.67 | 2.30 |
If you think the Bears win 63% of the time, −150 clears its 60% bar. If you think 58%, it doesn't, even though you still expect the Bears to win. And 60.0% + 43.5% = 103.5%: that extra 3.5% is the book's margin.
Terms in this lesson
OddsAmerican OddsImplied ProbabilityBreak-evenDecimal OddsFavoriteUnderdog