Betting Odds FAQ — Common Questions About Sports Odds Answered
Get answers to the most frequently asked questions about sports betting odds. Covers odds formats, payouts, vig, line movement, and more.
Understanding Odds
What do the + and - signs mean in betting odds?
The plus sign (+) indicates an underdog and shows how much you'd win on a $100 bet. The minus sign (-) indicates a favorite and shows how much you need to bet to win $100. For example, +200 means win $200 on a $100 bet, while -200 means bet $200 to win $100.
What is the difference between decimal and American odds?
American odds use + and - notation relative to $100. Decimal odds show total return per unit staked. For example, American +150 equals decimal 2.50. Both represent the same payout — they just display it differently.
How do I calculate implied probability from odds?
For decimal odds: Implied probability = 1 / Decimal. For American odds: Positive (underdog) probability = 100 / (Odds + 100). Negative (favorite) probability = |Odds| / (|Odds| + 100). Add the implied probabilities of both sides to find the vig percentage.
What is the vig (juice) in sports betting?
The vig is the commission the sportsbook charges for accepting your bet. It's built into the odds. Standard -110 vig means you risk $110 to win $100, giving the book roughly a 4.5% edge. Lower vig (like -105) is better for bettors.
Why do odds differ between sportsbooks?
Sportsbooks independently set odds based on their own models, liabilities, and market positions. Different books may have different opinions on a game's outcome, and they also adjust odds based on the betting action they receive. This creates opportunities for line shopping.
Line Movement and Shopping
What causes betting lines to move?
Lines move due to betting volume (especially sharp money), injury news, weather changes, and market correction. When a line opens at -3 and moves to -4, it typically means significant action came in on the favorite or new information changed the book's assessment.
What is line shopping and why does it matter?
Line shopping means comparing odds across multiple sportsbooks to find the best available price. Over an NFL season, getting a half-point better line on 50 bets can be the difference between a profitable and unprofitable year. Oddstatus makes line shopping easy by showing odds from all major books side by side.
What does it mean when odds are 'shaded'?
Shaded odds means the book has adjusted the line away from the fair market price, usually to attract action on a specific side. This often happens with popular public teams — the book may shade the price against them knowing the public will bet them regardless.