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How to Read Betting Odds and Lines

Written by: Richard Janvrin
10 min read

When you’re first getting into sports betting, the odds and betting lines can look like a completely different language.

+230 American odds, 2.00 European odds, 2/1 fractions. What does it all mean?

Regardless of whether you’re betting on the NFL, NBA, MLB, or NHL, odds express the probability of a bet winning and also how much the bet pays out depending on how much is wagered.

There are a few main ways to display odds and which one you’ll see usually depends on what part of the world the sportsbook is located. In the US the most common odds are called American odds. Some people call them money line odds.

The other two styles of odds you’ll see are called fractional (used mostly in the UK) and decimal (also known as European odds because they’re common in Europe).

In this article, we explain how each type of odds works step by step. We’ll use clear examples of each kind of bet and odds to show you exactly how to read betting lines. Follow our simple steps to learn to use the odds to your advantage.

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What Are Betting Odds and Lines?

When an oddsmaker proposes a wager, the public is given two or more betting options to choose from. For a single game, the choice is typically between Team A and Team B. Each option has its own chances of winning, which is reflected in the bet’s odds.

As a rule of thumb:

The shorter the odds, the higher the win probability, and the lower the payout.

That means that the better a team is, the less you’re going to win by betting on them since they win so frequently.

Bad teams are known as the underdog. They have lower win probability but bigger payouts.

When a team is the underdog it means they win less often. That translates to bigger payouts on your bet.

These odds can be expressed in any of the three main formats (American, fractions or decimals) and still reflect the exact same win probability. Different countries have their own preference for what kind of odds they use, and as we’ll learn, some sports are traditionally tied to a certain type of odds.

The good news is that if you’re betting online, you can often choose which kind of odds you want the site to use. Additionally, with online betting, you can just enter how much you want to bet and the sportsbook will tell you how much you can win, before actually placing the bet.

What Are Game Lines?

When comparing sportsbooks, you’ll come across another sports betting term that’s used interchangeably with odds: lines.

Odds and lines are almost the same thing, but the term “lines” is more specific than odds. It’s used to describe the odds available in a single event, otherwise known as game lines. The term “odds” is used for any bet under the sun, including props and futures.

Lines and odds are always changing. They change when new information comes in that influences the probability of an outcome, such as an injury to a star player, and can also change when there’s an imbalance of betting action between both sides of a wager.

Sportsbooks are always trying to balance the action between both sides in order to decrease their risk of exposure. In a perfect sports-betting world for the sportsbook, the exact same amount is bet on Team A as Team B. That way, they make a profit from the commission they charge regardless of which team wins.

For more on moving the line, take a look at our Wise Kracks podcast episode on Line Shopping.

How to Read Moneyline Bets and Odds

Any time you look at game lines for the four major American sports you’ll see a point spread, a money line, and a total. All three of these betting options incorporate American odds (also called moneyline odds), so learning how money lines work is a good starting point.

Moneyline odds are expressed in the hundreds (sometimes thousands) and always have a “+” or “-” in front of them. A positive money line denotes the underdog, while a negative one denotes the favorite.

The only exception is when both betting options are very close, and both have negative odds; in this case, the favorite has the number deeper within the negatives. For example, a -300 is a deeper negative than -125. If both odds are the same it means the sportsbook thinks both teams are evenly matched.

The negative and positive sign have more implications than simply indicating which betting option is more likely to win. It also indicates how much you can win on each bet.

  • Negative money line odds show how much money you’d have bet in order to win $100.
  • Positive money line odds show how much money you’d win on a $100 bet.

The $100 benchmark is simply an industry standard that makes it quick and easy to tell how much you’d win or need to stake. You can bet however much you want, and the payout will scale up or down to match the ratio. For example, staking $100 to win $50 could scale down to staking $10 to win $5.

To illustrate exactly how money line wagers work, we’ll use an NFL game line.

  • Miami Dolphins +280
  • Houston Texans -300

In this game, the Dolphins are the underdogs since they have positive odds. The Texans are the favorites, which you can tell by their negative odds.

  • Betting $100 on the Dolphins would yield a $380 total payout ($280 profit and your original $100 bet)
  • Betting $300 on the Texans, meanwhile, would yield a $400 total payout ($100 profit plus your original $300 bet back)

How to Read Point Spread Bets and Odds

Point spreads are the most popular way to bet on sports, as they provide people with bigger payouts when betting on favorites, and reduce the risk that comes with betting on underdogs.

That’s because the underdogs don’t have to win straight up; all they need to do is cover the spread in order for bets to pay out.

As is the case with the money line bets, point spreads are also expressed with negative and positive numbers. Also similar to money lines, a positive spread is used for the underdogs and a negative spread is used for the favorite.

We’ll use an example to show what we mean.

NBA Game Line: Point Spread

  • Atlanta Hawks +11 (-110)
  • Philadelphia 76ers -11 (-110)

The 11-point spread is positive for Atlanta, meaning they’re the underdogs in this matchup. In order for them to cover the spread, they need to win straight up, or lose by fewer than 11 points.

As for the 76ers, they’re the favorite so they need to win by at least 12 points in order to cover the spread.

So what happens if Philadelphia wins by exactly 11 points? Any time a favorite wins/underdog loses by the exact point spread, the result is a push, meaning the sportsbook returns all money staked.

For some sports, bookies usually include a half-point in their point spread in order to ensure a winning or losing result with no ties possible.

Just by looking at the point spread, you can’t tell how much money you’d win off a successful bet. For that, you need to check the money line odds in the brackets beside the spread.

These odds are usually a negative number and indicate how much money you’d need to wager in order to win $100. In the case of the Hawks/76ers example, both betting options have -110 money line odds in the brackets, meaning you’d have to bet $110 in order to win $100 in profit.

Depending on which sport you’re betting, the spread can be flexible or standard. A flexible spread means the oddsmaker can make it any number that makes sense. These are used for sports with lots of scoring, like NFL and NBA.

Sports with lower point production have standard point spreads which are the same number no matter what the matchup is.

For example, in MLB, the standard spread used is 1.5, with one team being designated the -1.5 favorite, and the other being the +1.5 underdog. NHL is another sport that uses standard spreads.

With standard spreads, you’ll also see more of a difference between the teams’ corresponding money line odds with the underdog producing a bigger payout compared to the favorite.

How to Read Over/Under Odds

Also known as Totals betting, Over/Under odds represent the total number of points or goals scored by both teams in a game.

This form of betting provides sports bettors with the opportunity to bet on whether they think the real total will go over or under the oddsmaker’s prediction which is called “the line”.

Let’s go through an example to show what we mean.

MLB Over/Under Odds

  • San Francisco Giants (O) 8 (-105)
  • Boston Red Sox (U) 8 (-115)

For this San Francisco Giants-Boston Red Sox game, oddsmakers are estimating that both teams will score a combined total of 8 runs. The public gets two options to bet: over 8 runs and under 8 runs.

  • If both teams combine for more than 8 runs, the over wins.
  • If both teams combine for fewer than 8 runs, the under wins.
  • If they combine for exactly 8 runs, the result is a push, and all bets are returned.

Totals payouts are based on the money line odds shown in the brackets beside the total, just like we covered in the money line example above.


  • Negative odds say how much money would need to be staked in order to win $100. In our example, the Over comes with -105 money line odds, so you’d have to bet $105 to win $100.
  • As for the Under (-115), you’d have to bet $115 to win $100, that’s the favorite.

How to Read Odds and Lines in Online Sportsbooks

Now that you know how odds work, it’s time to take a look at how they’re displayed in a typical online sportsbook.

Regardless of what sportsbook you’re using, when you look at game lines, the upcoming games for your chosen sport will be filtered based on time and date. The positioning of the teams tells you which one is the home team and which is the visiting team, as the home team is always positioned underneath the away team.

To the right of the teams are the three main kinds of bets we’ve covered so far: the spread, the money line and the total.

The spread and the total will look the same regardless of which sportsbook you use, but the moneyline odds could be displayed in American, decimal, or fractional styles. We’ll go into detail on all three kinds of odds later but for now here’s an example.

Teams Moneyline Spread Total
Oakland Raiders +125 +3 (-115) O 46.5 (-110)
San Francisco 49ers -145 -3 (-105) U 46.5 (-110)

Although these lines are expressed in American odds, most sportsbooks let you choose the type of odds you want the line expressed in. Changing the lines to decimal odds would look like this:

Teams Moneyline Spread Total
Oakland Raiders 2.25 +3 (1.87) O 46.5 (1.9)
San Francisco 49ers 1.69 -3 (1.95) U 46.5 (1.9)

How to Place a Sports Bet Online

Making bets at online sportsbooks is really simple. Follow these steps to get started:

  • To place a bet, click the bet or odds you want and they’ll automatically be added to your bet slip.
  • Once on the slip, type in the amount you want staked on the bet.
  • Your payout will be calculated automatically after you enter your bet amount.
  • Click the confirm button to finalize your bet and you’ll receive a ticket with your odds and the payout if you win.

Find the best sports betting bonuses in your state, here.

How to Read Odds and Lines in Land-Based Casinos

You can make the same wagers in land-based casinos and sportsbook as you can online. In both cases you usually have the option to bet on the point spread, money line, and total. Some sports also prop bets like futures.

The big difference between betting in Vegas, for example, and betting online is how the bets are displayed.

Here’s an example of an NFL game line might be displayed in a land-based casino:

Rotation Number Team Name Total/Spread Moneyline Odds
309 Pittsburgh Steelers 46 +210
310 New England Patriots -7.5 -275

Looking at a Las Vegas odds board can be intimidating for beginners because each set of odds isn’t clearly marked the same way they are with online sportsbooks. In the example above, we added headers in the top row for clarity, but they wouldn’t be included on an actual land-based casino odds board.

There are five components to the land-based casino odds board.

  1. Rotation Number: Each betting option has a unique rotation number, which is like a serial number. This helps the bookie quickly identify the bet you want.
  2. Team: The team name is displayed on the board for your reference only. The bookie prefers to use the rotation number to process your bet.
  3. Total/Spread: The number with the negative sign is the spread. This is placed beside the favorite. You can assume that the other team has the positive inversion of that same spread.
  4. The total is placed in the same column as the spread. It’s the only number with no positive or negative sign attached to it.
  5. Moneyline odds are displayed for each team. If you want to bet on the money line, you must specify this to the bookie, as the spread is the default bet.

To place a bet at a Vegas sportsbook counter, simply tell the bookie “X dollars on [rotation number] point spread.” Using the example above, you could say: “$80 on 310 point spread please.”

Always double check your bet slip to make sure the bookie entered it right before leaving the counter.

How to Read Three Main Kinds of Betting Odds

As mentioned, there are three ways sportsbooks display odds: American odds, decimal odds, and fractional odds. While you can always use an odds calculator to convert one type of odds to another, you’ll benefit from learning how each type works.

Don’t worry. Once you learn the basics they’re all really easy to understand. We’ll cover all three types and discuss their pros and cons, starting with American odds.

American Odds

American sportsbooks’ odds of choice are American odds, which are expressed as a positive or negative number in the hundreds (sometimes thousands). When looking at American odds, you might see one team listed as -150 to beat a +125 underdog. These odds tell you:

  • How probable an outcome is for either side to win.
  • How much money you can win from a $100 underdog bet.
  • How much money you’d have to bet on the favorite to win $100.

Pro: The underdog and favorite are clearly indicated. The underdog is the team with the negative number and the favorite is the team with the positive number.

Con: There are two payout calculations, one for the favorite and one for the underdog.

In order to understand how American odds work, let’s use an MLB example from the 2018 World Series.

MLB Game Line: American Odds

  • Los Angeles Dodgers +125
  • Boston Red Sox -150

In this game line, the Boston Red Sox are -150 favorites to beat the +125 Los Angeles Dodgers. We can tell that the Red Sox are favored to beat the Dodgers because the Red Sox’s odds are negative, and the Dodgers’ odds are positive. Remember, positive odds indicate the underdog, and negative odds indicate the favorite.

  • Exception: Sometimes, you’ll come across both teams having negative odds. This happens when the teams are near-perfect matches. In these scenarios, the team with the deeper negative number is the favorite. For example, if the Dodgers were -115, and the Red Sox were -125, the Red Sox would be the favorites.

American Odd Payouts

Simply by looking at American odds, you can see how much money can be won based on $100 betting increments. Since a higher payout is always offered for the riskier option, the underdog’s odds use the following payout calculation:

  • Underdog odds = Amount of profit based on $100 stake.

These odds tell you how much money you would win on a $100 bet; in the case of the Dodgers, you’d win $125 profit from a $100 bet.

The favorite, meanwhile, has a lower payout because their odds of winning are higher. Odds for the favorite are based on the following formula:

  • Favorite odds = Stake needed to win $100 profit.

In other words, the favorite’s odds tell you how much you’d have to bet in order to win $100. In the case of the Red Sox in our example, you’d need to bet $150 to win $100.

The $100 scale used with American odds lets bettors see the value of American odds right away; you can bet however much you want, provided you stick to the maximums and minimums outlined in your sportsbook.

In addition to being able to clearly identify the favorite in a game and easily see how much you’d win from betting on both options, American odds tell you how likely one team is to beat the other with a concept known as implied probability.

In order to figure out the implied probability of each side winning, two calculations need to be done, one for the underdog and one for the favorite. We’ll go through both using the same Dodgers-Red Sox odds from our example.

Three-Step Calculation for Implied Probability of Underdog

First let’s calculate the implied probability of the Los Angeles Dodgers winning with odds of +125

  1. Add 100 to the positive odds (125 + 100 = 225)
  2. Divide 100 by the sum of the calculation in Step 1 (100 ÷ 225 = 0.44)
  3. Take the quotient and multiply it by 100 to convert it to a percentage (0.44 x 100 = 44%)

Our calculation shows that the oddsmaker believes the Dodgers have a 44% chance of beating the Red Sox.

Four-Step Calculation for Implied Probability of Favorite

Calculating the odds of the favorite winning takes one extra step but it’s still really straightforward.

Follow along as we calculate the implied probability for the Boston Red Sox with odds of -150

  1. Take the negative odds and flip them to positive odds (-150 becomes 150)
  2. Take the new positive odds and add 100 (150 + 100 = 250)
  3. Take the positive odds from the first step and divide it by the sum of the addition in the second step (150 ÷ 250 = 0.6)
  4. Multiply the quotient by 100 to convert it to a percentage (0.6 x 100 = 60%)

Now we know that the Red Sox’s odds have an implied win probability of 60%. If you think that seems low, scoop up the odds and lock in the bet.

Decimal Odds

Across the pond in the UK, the sports betting market deals mainly in decimal odds, which are essentially payout multipliers. They’re even easier to understand than American odds.

If you see, for example, one team listed as 3.25 to beat another team, you’re looking at decimal odds.

These odds tell you:

  • The probability of the bet winning.
  • How much you’d win, based on how much you bet.
  • Which team is the favorite and which is the underdog.

Pro: Easy to determine implied probability.

Con: Payout includes the return of your stake, not just the profit like American odds.

We’ll continue with the same MLB example with the Dodgers and Red Sox except this time we’ll show you the same odds in decimal style.

MLB Game Line: Decimal Odds

  • Los Angeles Dodgers 2.25
  • Boston Red Sox 1.67

In this example, the Boston Red Sox are 1.67 favorites to beat the 2.25 Los Angeles Dodgers. You can tell that the Red Sox are the favorites because their decimal odds are smaller, meaning their bet offers a smaller payout multiplier than the 2.25 Dodgers.

Like we mentioned before, the favorite always has a lower payout to balance the higher odds of winning.

Decimal Odds Payouts

To determine how much money either bet will yield if it wins, simply multiply your stake by the decimal odds. We’ll use a $50 stake as an example.

  • Los Angeles Dodgers: $50 X 2.25 = $112.50
  • Boston Red Sox: $50 x 1.67 = $83.50
  • A $50 bet on the Dodgers would yield a $112.50 payout, which includes the return of your $50 stake and a profit of $62.50.
  • A $50 bet on the Red Sox would yield an $83.50 payout, which also includes the return of the $50 staked and a profit of $33.50.

Determining the implied probability of each bet is easier with decimal odds than it is with American odds. One calculation is used for both teams.

Two-Step Calculation for Implied Probability with Decimal Odds

Los Angeles Dodgers 2.25

  1. Divide 1 by the decimal odds (1 ÷ 25 = 0.44)
  2. Take the quotient and multiply it by 100 to convert it to a percentage (0.44 x 100 = 44%)

The implied probability for the Dodgers winning is 44%. Let’s repeat the exercise with the Boston Red Sox’s decimal odds of 1.67.

  1. Divide 1 by the decimal odds (1 ÷ 67 = 0.6)
  2. Take the quotient and multiply it by 100 to convert it to a percentage (0.6 x 100 = 60%)

The implied probability for the Red Sox winning is 60%. If you think that they actually have a higher probability than that, take the bet. Alternatively, if you think the Dodgers have a better chance of beating Boston than 44%, take the Boston bet.

After all, sports handicappers are regular people who use their judgment and knowledge to assess probability; they’re subject to the same biases and errors as everyone else.

Fractional Odds

Often used for horse racing and prop bets in other major sports, fractional odds represent how much you’d earn based on a certain stake.

Fractional odds are also really easy to understand. Just remember that:

  • The fraction’s numerator represents the profit.
  • The fraction’s denominator represents the stake (your bet).

For example, 2/1 fractional odds mean you’d win 2 units for every 1 unit staked.

These odds tell you:

  • The probability of the betting outcome.
  • A simple payout to stake ratio.

Pro: The profit is clear; it’s not lumped together with the return of your bet.

Con: If the fractions for both teams have different denominators it can be hard to tell which option is the favorite.

We’ll continue with the same MLB example from before to show you how fractional odds work.

MLB Game Line: Fractional Odds

  • Los Angeles Dodgers 5/4
  • Boston Red Sox 2/3

For the Dodgers, every 4 units you bet will pay 5 units as profit. So a $4 bet on the Dodgers would yield $5 in profit. If you want to know the total return, including the amount staked, simply add the denominator to the numerator. In this instance, you’d add $4 to $5 for a total return of $9.

A $3 bet on the Red Sox, meanwhile, would earn $2 in profit. The total return (including the original stake) would be $5.

When getting started with fractional odds, you may need to calculate the payout for each betting option to figure out which team is the underdog and which is the favorite because it’s not as clear as it is with American and decimal odds.

The team with the higher payout is always the underdog.

Calculating the implied probability of each betting option using fractional odds involves a three-step equation. We’ll go through it using our baseball example to determine the implied probability of each team winning.

Three-Step Calculation for Implied Probability Using Fractional Odds

Just like American and decimal odds, we can use fractional odds to figure out how likely the sportsbook things the bet is to win. First let’s calculate the implied probability for the LA Dodgers with fractional odds of 5/4:

  • Add the denominator and numerator together (5 + 4 = 9)
  • Divide the denominator by the sum calculated in Step 1 (4 ÷ 9 = 0.44)
  • Multiply the quotient by 100 to convert it to a percentage (0.44 x 100 = 44%)

According to the math, the Dodgers’ have a 44% implied probability of winning their game against the Red Sox. If you think they’re chances are actually higher, this is a value bet.

Now let’s do the calculation for the Red Sox with fractional odds of 2/3:

  • Add the denominator and numerator together (2 + 3 = 5)
  • Divide the denominator by the sum calculated in Step 1 (3 ÷ 5 = 0.6)
  • Multiply the quotient by 100 to convert it to a percentage (0.6 x 100 = 60%)

So there you have it. The Red Sox have a 60% implied probability of beating the Dodgers according to the odds, regardless of whether you’re using American, decimal or fractional odds.

Now that you know what betting odds are and how to read them, you’re ready to join a sportsbook, be it land-based or online, and put some money on your favorite team.

Legal betting is becoming available in more and more states thanks to a big decision made by the US Supreme Court in 2018.

Since 1992 the only state that had full legal sports betting was Nevada but now, thanks to the SCOTUS decision, each state has the authority to create their own laws around sports gambling.

A number of states have already begun offering legal betting and tons more are getting their legislative wheels turning in order to introduce it soon.

For the latest developments for your state, check out our comprehensive state by state guide to legal US sports betting. We’re updating it daily as more states enter this multi-billion dollar industry.

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Richard Janvrin

567 Articles

After graduating from the University of New Hampshire with a BA in Journalism, Richard Janvrin has been covering iGaming and sports betting since December 2018. Richard has covered betting at Bleacher Report, Gambling.com, The Game Day, Forbes, and more.

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