Sports Betting Numbers Explained

1. Understanding American Odds

American odds use a base of $100. Negative odds (-150) indicate the favorite. Positive odds (+200) indicate the underdog. The further from +/-100, the stronger the favorite or underdog.

Convert American to decimal: Decimal = (100/|American|)+1 for negative odds (-150 becomes 1.67). Decimal = (American/100)+1 for positive odds (+200 becomes 3.00).

The key number is the break-even percentage. At -110, the implied probability is 52.38%. You need to win 52.38% of spread bets just to break even. Always seek the best price.

2. Point Spreads Explained

The point spread is a handicap to create balanced betting. The favorite must win by more than the spread. The .5 eliminates pushes. Understanding key numbers (3, 7 in football) helps identify value.

Spread movement is driven by betting action. If heavy money comes in on the favorite, the spread moves. Following line movement reveals where sharp money is going.

Sportsbooks like DraftKings and FanDuel display line movement charts showing where betting action is concentrated.

3. Over/Under (Totals) Explained

The sportsbook sets a total points line and you bet over or under. The half-point prevents pushes. Understanding what drives scoring is key to profitable totals betting.

For NBA totals, factors include pace, offensive efficiency, and rest days. In the NFL, quarterback quality, pass defense, and weather matter.

Totals respond to situational factors. Back-to-back NBA games often score lower. Division rivalry football games are often lower scoring due to familiarity.

4. Decimal and Fractional Odds

Decimal odds show total return per unit staked including stake. 2.50 odds mean $100 returns $250. Profit = stake x (decimal odds - 1). The simplest for implied probability: 100/decimal.

Fractional odds are traditional in UK racing. 5/1 means win $5 profit per $1 bet. Evens (1/1) doubles money. Convert to implied probability: denominator/(denominator+numerator)x100.

Most sportsbooks let you toggle between formats. Choose the one that makes most sense and stick with it.

5. Vig, Juice, and the Bookmaker Edge

The vig is the bookmaker commission built into every bet. On -110/-110 spread, total implied probability is 104.76%. The extra 4.76% above 100% is the bookmaker profit margin.

Reduced vig at -105/-105 requires only 51.22% wins to break even. Over 1,000 bets at $100 each, a -105 bettor saves $1,160 in vig compared to -110.

Different markets have varying vig. Player props have higher vig. Futures and parlays have the worst vig. Focus on low-vig markets.

6. Calculating Payouts and Expected Value

Calculate payouts: negative odds payout = (stake/|odds|) x 100. Positive odds payout = (stake x odds)/100. Decimal return = stake x decimal odds.

Expected value (EV) is the most important concept. EV = (win probability x amount won) - (loss probability x amount lost). Positive EV bets are the foundation of profitable betting.

Compare your estimated probability to implied probability from odds. If yours is higher, you found value. If not, skip the bet regardless of confidence.

Frequently Asked Questions