What is a Betting Line?
A betting line is the gambling odds set by bookmakers on a specific game or event. These odds determine the favorite, the underdog, and the parameters of the two-way wagering.
The most common betting lines are point spreads, moneylines, and totals.
For example, let’s say the Steelers play the Bengals in Cincinnati. Here’s an example of a betting line for that game:
- Pittsburgh Steelers +6 (-110)/+198/O44.5
- Cincinnati Bengals -6 (-110)/-240/U44.5
What do these numbers mean? Line interpretation is the first step to reading line movement.
Point Spread
In this example, the ‘6’ is the point spread. A spread bet on the Steelers cashes if they lose by less than six or win the game.
The -110 is the juice or vig on the point spread. The -110 means that you must bet $110 to win $100. Another way to think about the vig is a 10% fee you pay to the sportsbook when you make a wager. This fee is how sportsbooks make a considerable amount of profit.
Moneyline
A moneyline wager is a bet to win. If you believe the Steelers will win, you could bet them at +198 odds meaning a $100 play wins you $198 if the Steelers win. Should you bet the favored Bengals at -240, you’d have to lay $240 to win $100.
Total
Totals are also known as over/under wagers. In this example, you could bet that the Steelers and Bengals will combine for more than 44.5 points. Or you could bet they’ll score less than that amount.
The juice on each side is -110.
Why Do Betting Lines Move?
Bookmakers set the lines, and when released, the market opens for betting. Bettors place wagers, and these wagers can move the betting lines. The Steelers open as +6 underdogs on Monday, but that number will fluctuate throughout the week.
The theoretical goal of bookmakers is to get an even amount of money wagered on each side of the bet. By doing so, they’re guaranteed a profit from the vig they collect on each wager.
The theory is different from reality. Betting lines move for various reasons. Correctly interpreting line movement separates sharps from squares.
One Side Receives Majority of Bets
Sportsbooks want to keep the amount of money on each side of an offered bet as even as possible. Doing so ensures they won’t lose money, and they’ll rake in the vig charged on each bet.
Line movement is how they attempt to keep that balance.
The Steelers open at +6 and receive an overwhelming majority of bet tickets and money. The sportsbook will move the 6 to 5.5 or 5 to attract play on the Bengals side.
A Sharp Makes a Play
Bookmakers know who the best players are and respect their opinion. These players, known as sharps, are astute handicappers and may have an information edge.
Let’s say a sharp player bet on the Bengals at -6. Though the sportsbook sees more bets and money on the Steelers’ side, they’ll move the line to Bengals -6.5 or -7.
External Factors
Betting lines also move due to player injuries, weather reports, and other external factors.
The week before the Bengals game, Steelers starting QB Mitch Trubisky tore his ACL in practice. When that injury information gets released, the book will adjust its line no matter the amount of action. A +6 may move to a +8 or +9 due to this news.
A dramatic line movement often indicates a personnel issue like an injury or suspension. If you notice a drastic change, you might want to check the injury reports and latest team news before making a bet.