Betting Basics

How To Read Odds

August 22, 2023

For newcomers to sports gambling, the first time you encounter the information on a betting slip may feel like an attempt to decipher Sanskrit. What does a +250 moneyline mean? How about a -6 pt spread at -110? How much would you win for a first-to-score-a-touchdown prop at +2500?

These numbers on the slip are the betting odds, and to make money gambling, you need to know how they work and what they mean.

In other words, you need to learn how to read the odds.

Fortunately, reading the odds is easier than it may appear at first glance. By the end of this comprehensive betting guide, you’ll be able to confidently place your bets like a pro.


What Are Odds?

In sports gambling, the odds are a numerical representation of the likelihood of a particular event occurring, such as one team winning or a player scoring during the game. Odds help you determine whether a certain wager is worth pursuing and determine how much the wager would pay out in the event of a win.

In sports gambling, odds are inversely related to probability. So, the greater the chance of an outcome occurring, the lower the odds will be.

Typically, most sports matchups will have a clear favorite and an underdog. Sportsbooks will establish an initial line based on numerous factors, including:

  • Team performance
  • Home field advantage
  • Public perception
  • Historical trends
  • Weather conditions
  • Player injuries
  • Travel schedules

This line will likely include the expected winner, points totals, and margin of victory—all of which bettors can wager on. The odds for that initial line will be modified as the week progresses, factors change, and bets from the general public stream in.

What Is Vig?

Few, if any sportsbooks will ever offer odds that are more favorable than -110. Meaning, you need to bet 110 to make 100.

That extra $10 is known as the vigorish—more colloquially as the juice.

The vig is the surcharge sports book add-on to ensure that they will make money for offering, processing, and paying out wagers, regardless of the outcome of the game. Instead of simply adding a surcharge fee after the fact, they typically build it into the odds of the bet.

For bookies, the ultimate goal is to set the line and odds so that nearly an identical amount of money is placed on either side. When that ideal outcome occurs, the winners get paid out by the money the losers spent on betting, and the extra 10% of the cost that typically comes with any bet goes straight into the bookie’s pocket. Consider this example from Forbes:

“Let’s pretend the Chicago Bears and Detroit Lions are playing each other, and both are listed at -110 to cover the spread. In this scenario, let’s say the sportsbook takes $25,000 in bets on the Bears and $25,000 on the Lions for a total handle of $50,000. Regardless of who wins, the sportsbook pays out $22,727.27 to the winners (and returns their $25,000 in stakes) but still earns a profit of $2,272.73 thanks to the money gained from the losing bets.”

The vig may vary for any given sportsbook, which is why savvy bettors typically shop around to find the best odds available to minimize the vig payment and maximize the potential profits.

Types Of Odds

Sportsbooks typically display their odds in one of three styles:

Decimal Odds

A popular format in Europe and Australia, decimal odds are expressed as a decimal number greater than or equal to one (if it were any lower than 1, it would result in a net loss, even if the bet hit). This figure represents the total return on a $1 bet, including the initial stake.

The calculation for decimal odds is: money risked X odds = total payout.

For instance, if you see odds of 4.00 on a bet slip, that means a winning $1 bet would result in a total return of $4, including your initial stake.

Fractional Odds

Although some American sportsbooks use fractional odds, this method is more commonly used outside of the country, particularly in the UK and Ireland.

These are expressed as a fraction, representing the ratio of the potential profit to the initial stake.

For example, if you see odds of 4/1 on a bet, that means a winning $1 bet would result in a total return of $4, plus your $1 initial stake. Fractional odds also include the initial stake in the payout, so a $1 winning bet at 4/1 odds would result in a profit of $4.

American Odds

American odds, also known as moneyline odds, are likely the most confusing to newcomers. The odds are typically expressed as a positive (+) or negative (-) in relation to bets of $100. But how they relate depends on whether the bet is the favorite (-) or the underdog (+).

For example, if the odds were -110, you would need to bet $110 to make $100. If the odds were +110, you would need to bet $100 to make $110.

Reading American Odds And Lines

When looking to place a bet, it’s always important to understand how to read sports betting lines. Let’s assume you’re interested in placing a sports wager on a baseball game. Here’s what a betting slip might look using American odds:

This simple slip provides 6 basic gambling options:

  • Dodgers to win (moneyline)
  • Dodgers +1.5 (runline)
  • Over 7.5 runs (total)
  • Giants to win (moneyline)
  • Giants -1.5 (runline)
  • Under 7.5 runs (total)

But what do those mean?


The simplest of all bets, the moneyline is a straight bet on which team you believe will win the game. In this instance, the Dodgers have a -155 moneyline, meaning that you would need to bet $155 on them to win outright in order to make $100 profit. Conversely, the Giants have a +135 moneyline, meaning that if you bet $100 on them to win, you would win $135 if they won.


Referred to as the spread in other sports, the runline is a wager on whether one team will win or lose by a certain number of runs.

With this slip, Dodgers are favored by 1.5 runs, which means that they need to win by at least 2 runs in order for a bet on them to be successful. The Giants, on the other hand, can either win the game outright or lose by no more than 1 run in order for a bet on them to be successful.

A $110 bet on the Dodgers spread would result in $100 in winnings, whereas you would need to bet $130 on the Giants spread to win $100. In this case, you can tell that the book thinks that it’s slightly more likely that the Giants cover the spread than the Dodgers.

Totals (Over/Under)

This is a bet on the total number of runs scored by both teams in the game.

For this game, the over/under is set at 7.5 runs. As the bettor, you can decide whether you think the total number of runs scored will be over or under that number.

The odds for the over bet are -105, meaning that you would need to bet $105 to win $100 if the total runs scored are over 7.5. The odds for the under bet are -115, meaning that you would win $100 for every $115 bet on the total runs scored being under 7.5.

Converting Odds

Today, there are plenty of online odd converter calculators available to interested bettors. That said, here are the formulas for how to perform these conversions by hand:

Now that reading odds is no longer confusing, it’s time to test your luck. Be sure to check out the variety of sports you can bet on with Tipico including our NFL Sportsbook among others!


Tipico staff contributions