Sports Betting Odds, Explained
Moneylines, spreads, totals, and the math that turns a price into a probability — in plain English, with examples.
American odds use a baseline of $100. A negativenumber marks the favorite and shows how much you’d risk to win $100: at −150, you stake $150 to win $100. A positive number marks the underdog and shows the profit on a $100 stake: at +130, a $100 bet wins $130. The bigger the negative number, the heavier the favorite; the bigger the positive number, the longer the shot.
Every price implies a win chance. The formulas:
- Favorite (−): odds ÷ (odds + 100). So −150 → 150 ÷ 250 = 60%.
- Underdog (+): 100 ÷ (odds + 100). So +130 → 100 ÷ 230 ≈ 43%.
This “implied probability” is exactly what MatchupLens uses as the backbone of its win-probability estimate when a market line is available.
In the example above, 60% + 43% = 103%. That extra 3% is the vig(also called juice or the overround) — the sportsbook’s built-in margin. To get a clean estimate, you “de-vig” by rescaling the two implied probabilities back to 100%. It’s why a fair model can land a few points off the raw number printed on the line.
A spread handicaps the favorite to even out a lopsided matchup. If a team is −6.5, they must win by 7 or more to cover; their opponent at +6.5 covers by losing by 6 or fewer — or winning outright. The half-point (the “hook”) exists to prevent ties. A team can win the game and still fail to cover, which is why spread results and straight-up results often disagree.
The total is the projected combined score of both teams; you can wager whether the real total lands over or under it. When a whole number is involved and the result lands exactly on it — say a spread of −6 and a 6-point win — the bet is a push, a tie against the line, and stakes are usually refunded.
We treat the market as the single strongest signal available. When a moneyline exists, we convert it to implied probability, remove the vig, and use that as our win-probability base; when it doesn’t, we fall back to team records plus home advantage. We display the spread and total for context only. For the complete approach, see our methodology and the glossary.
This guide is educational and is not betting advice. Odds and availability vary by sportsbook and by state. If you choose to wager, do so responsibly and only where legal. 21+. Gambling problem? Call 1-800-GAMBLER. Responsible gambling resources →