Professional Sports Betting
Introduction to Sports Betting
How Betting Works
Sports betting revolves around a simple idea: predicting the outcome of a game. But who sets the terms and handles the money? That's the job of a bookmaker.
Bookmaker
noun
A person or organization that accepts bets on sporting events at agreed-upon odds. Often called a "bookie" or a "sportsbook."
A bookmaker's goal is to make a profit regardless of who wins. They do this by setting odds that attract bets on both sides of a contest and by charging a commission on losing bets. This built-in advantage is known as the vigorish, or "vig."
Think of it like a coin toss. The true odds are 50/50 for heads or tails. A bookmaker, however, won't pay you even money. Instead of offering odds that pay $100 on a $100 bet, they might require you to bet $110 to win $100. That extra $10 is the vig. If they take an equal amount of money on both heads and tails, they are guaranteed a profit from the losing side's commission.
Understanding the Odds
Odds tell you two things: the implied probability of an outcome and how much money you can win. They can look confusing at first because they come in a few different formats. The three most common are American, decimal, and fractional.
American (Moneyline) Odds: These are the most common in the United States. They are shown with a plus (+) or minus (-) sign. A minus sign indicates the favorite (the team more likely to win), while a plus sign indicates the underdog.
- -150: You must bet 💲150 to win 💲100.
- +130: A 💲100 bet will win you 💲130.
The minus number shows how much you need to risk to win $100. The plus number shows how much you win for every $100 you risk.
Decimal Odds: Popular in Europe, Australia, and Canada, decimal odds are straightforward. The number represents the total payout for every 💲1 wagered, including your original stake.
- 1.67: A 💲100 bet pays out 💲167 (💲67 profit + 💲100 stake).
- 2.30: A 💲100 bet pays out 💲230 (💲130 profit + 💲100 stake).
Any decimal odd above 2.00 means the team is an underdog.
Fractional Odds: Common in the UK and Ireland, these odds are presented as a fraction. They show you the potential profit relative to your stake.
- 2/3: For every 💲3 you bet, you will win 💲2 in profit.
- 13/10: For every 💲10 you bet, you will win 💲13 in profit.
| Odds Format | Team A (Favorite) | Team B (Underdog) |
|---|---|---|
| American | -150 | +130 |
| Decimal | 1.67 | 2.30 |
| Fractional | 2/3 | 13/10 |
Common Types of Bets
Once you understand the odds, you can explore different kinds of bets. While there are many exotic options, most wagers fall into a few key categories.
Moneyline: The simplest bet. You are just picking which team will win the game outright. Odds are used to balance the betting, so you'll win less money betting on the favorite than on the underdog.
If Team A is a -150 favorite, a $150 bet wins you $100. If Team B is a +130 underdog and they win, your $100 bet wins you $130.
Point Spread: This bet isn't about who wins, but by how much. The favorite is given a point handicap (e.g., -7.5), and the underdog gets a point advantage (e.g., +7.5). To win a bet on the favorite, they must win by more than the spread. To win a bet on the underdog, they must either win the game or lose by less than the spread.
For example, if you bet on a basketball team at -7.5, they must win the game by 8 points or more for your bet to cash. The spread makes games between mismatched teams more interesting from a betting perspective.
Totals (Over/Under): The bookmaker sets a number for the total combined points scored in a game by both teams. You bet on whether the actual total will be over or under that number. It doesn't matter who wins or loses.
If the Over/Under for a football game is 48.5 points, and the final score is 28-24 (a total of 52), the "Over" bets win.
Parlay: A parlay combines two or more individual bets into a single wager. To win a parlay, all of your individual bets (called "legs") must be correct. If even one leg loses, the entire parlay loses. The appeal is a much higher payout than you'd get from placing each bet separately.
Combining a moneyline bet on one game with an Over/Under bet on another is a simple two-leg parlay. The more legs you add, the higher the potential payout—and the higher the risk.
Now that you've got the basics down, let's review some key terms.
Ready to test your knowledge? Let's see what you've learned.
What is the primary purpose of the "vigorish" or "vig" for a bookmaker?
A team is listed with American odds of +130. How much profit would you make on a successful $100 bet?
Understanding these core concepts—the role of bookmakers, how to read odds, and the most common bet types—is the first step into the world of sports betting. With this foundation, you can begin to explore the space more confidently.