Understanding Betting Odds
Odds represent the relationship between the payout and the probability that a sportsbook assigns to an event. There are three major formats: American (moneyline), Decimal, and Fractional — and all three express the same information, just differently.
The Vig (House Edge)
Sportsbooks don't offer true odds — they add a margin called the vig or juice. At -110 on both sides, the implied probabilities sum to 104.8% (52.4% + 52.4%), meaning the book expects to keep 4.8% of all money wagered. This is why shopping for the best odds matters: getting +100 instead of -110 on a 50/50 bet eliminates the vig entirely.
Why Odds Shopping Matters
Over 1,000 bets at -110 vs +100 on the same 50/50 markets: at -110 you'd expect to lose ~$4,800 due to vig. At +100 you'd break even. This is why serious bettors use 3-5 different sportsbook accounts to always get the best available price.