When the oddsmakers release (also known as opening) a line on a game, the first thing they do is decide which team should be the favorite and which should be the underdog. The favorite is the team that is expected to win the game, while the underdog is expected to lose. If the game is a toss-up, books will open it as a “pick” or “pick’em.”
2. Spreads
There are two different ways to bet on a favorite or an underdog. The first is the point spread. This is based on which team will cover. A favorite “gives” points, while an underdog “gets” points. For example, say the Patriots are 7-point favorites (-7) against the Jets.
If you bet on the Patriots, they need to win the game by 8 points or more for you to win your bet. If the Patriots win by 8 points or more, you “cover.” If the Patriots win by exactly 7 points, that is called a “push,” which means you get back the money you originally bet. If the Patriots win by 6 points or fewer (or lose the game straight-up), you lose your bet.
On the flip side, if you bet on the Jets “plus the points” (+7), you need the Jets to either win the game or lose by six points or fewer for you to win (or cover) your bet.
Spreads are available for all sports, but they are predominantly used when betting on football and basketball.
3. Moneylines
The second way to bet on a favorite or an underdog is on the moneyline. This is based solely on which team will win the game. Favorites are given a “minus” designation, such as -150, -200 or -500. If a favorite is -200, that means you have to risk $200 to win $100. If the favorite wins, you get $100, but if the favorite loses, you’re out $200. Because favorites are expected to win, you assume more risk when betting on them.
Underdogs are given a “plus” designation, such as +150, +200 or +500. If an underdog is +200, that means if you bet $100 on them and they win the game, you get $200. If they lose the game, you lose only the $100 that you risked. Because underdogs are expected to lose, there is more of a reward when betting on them.
Moneylines are available for all sports, but they are predominantly used when betting on baseball, hockey and soccer.
4. Over/Unders (Totals)
In addition to setting a line for the favorite and the underdog, oddsmakers will also set a total number of points scored in a game (by both teams combined). This is called the “total” or the “over/under.” Bettors can then wager on whether or not the game will go Over or Under the total.
For example, an NBA game between the Celtics and Bulls might have a total of 215. You could either bet the Over 215 or the Under 215. If you bet the Over 215 and the total points scored end up being 216 or higher, you win your bet. If the total points scored are 214 or fewer, you lose.
5. What is the -110 number listed next to my bet?
The oddsmakers put a “tax” on every bet, which is typically called the “juice,” “takeout” or “vig” (short for “vigorish”). The juice is the commission you have to pay to the sportsbook for them to accept your wager. Say the Duke Blue Devils are -5 (-110) … that means if you want to bet on Duke as a 5-point favorite, you need to risk $110 to win $100.
The juice can also be a positive number, such as Penn State -7 (+110). That means if you bet $100 on Penn State as a 7-point favorite and it covers, you win $110. If it loses, you lose only the $100 that you risked.
Resourse: https://actionnetwork.com/how-to-bet-on-sports/general/