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Sports Betting Odds & Why They Differ Between Bookies

Sports betting sites sometimes offer completely different odds, even on the same match and wager. There are also sites that are dedicated to comparing these sports betting odds between bookies.

sports betting odds

The above scenario isn’t uncommon. On the contrary, a huge part of sports betting relies upon these differing odds or coefficients.

Why the difference, though? What does it mean? How is it calculated? Can you use it to your advantage?

We intend to answer all of these questions and more. We’ll also give you a few pointers on how to implement your new-found knowledge.

What are Sports Betting Odds?

Before we unravel the inner workings of sports betting odds, and why they differ, it’s crucial to understand what they are. Put simply, odds are the likelihood of a specific event occurring.

In sports betting, this represents the “implied probability” of a team or competitor winning a game or match. At a glance, you can determine who’s more likely to win by looking at which team/player has the lowest odds.

When you place a bet on a team/player with lower coefficients (sometimes referred to as the “favourite”), your chances of being successful are better than if you place a bet on higher odds.

For this reason, a successful wager on the team/player with higher odds (sometimes referred to as the “underdog”) will produce a higher payout. This is where the saying “the higher the risk, the higher the reward” comes from.

  • Higher Odds = Higher Payouts (Less likely to win – The Underdog)
  • Lower Odds = Lower Payouts (More likely to win – The Favourite)

Odds can come in one of three formats. These include fractional, decimal or American. Many sports betting sites give you the ability to toggle between the three because the difference in format doesn’t affect the odds whatsoever.




How Are Odds Calculated?

Now that we’ve covered the different formats, and what sports betting odds are, the next step is to know how they’re calculated. Once you understand this, you’ll also see why different sports betting sites offer different coefficients.

odds calculated

The Bookmaking Business – Balancing The Books
Bookmakers are businesses first and foremost. The goal of any business is to turn a profit. When bookies determine the coefficients of a game, they take a variety of factors, their margin included, into consideration. A successful bookmaker calculates the odds in such a way so that they still get their profit, regardless of who wins. The odds need to be attractive enough for punters to place bets on both sides of the betting market though; otherwise, there’d be no point. By balancing the books (and therefore liability), a bookie can make a profit, no matter the outcome.

Implied Probability vs Real Probability
Previously, we mentioned that odds reflect the “implied probability” of something happening. In order for bookmakers to balance the books, to build in their margin and to turn a profit, the real probability of a game must be calculated ahead of time. This is gleaned from statistics, historical data, form and to a large extent, human opinion (their own, their competitor’s and the public’s).

More Data = Better Value
The more information that’s available, the better the real probability will be reflected and, therefore, the implied probability; ultimately, this is what affects the sports betting odds.

For example, football odds are good value and incredibly competitive because of the sheer amount of data that’s available.

On the other hand, Niche betting markets like the winner of Britain’s Got Talent to tend to have higher margins built-in because there’s less data on the basis of which to predict an outcome. Bookies do this to negate risk as part of balancing their books.

The Margin, Edge, Vig, Vigorish, Juice or Overround
You might’ve seen some of the above terms bandied about on the internet. A bookie’s margin, as discussed previously, is also sometimes referred to using one of these terms.

Once the real probability is calculated, a betting site subtracts its margin and presents you with the odds. As an example, let’s say the actual probability is calculated at 3.00 (or 2/1 in fractional). If the vig, edge or margin is set at 5%, then the odds on offer are set at 2.90 (or 19/10).

The implied probability is, therefore, not entirely reflective of the true coefficients, but instead, it includes the bookmaker’s margin.

How Are Odds Priced?

Each bookie prices their odds according to the principles we’ve mentioned above. However, there’s another critical component that’s factored in, too, which ties in with balancing books.

A sports betting site has calculated the real probability and applied its margin. If all punters decided to bet on that one outcome alone, then the incoming bets would be imbalanced or skewed. To achieve equilibrium, a bookie increases its margin on the popular line or decreases its margin on the less popular odds to either encourage or discourage betting.

Ironically, this isn’t left up to fate. Instead, bookmakers analyse their punter base to predict which markets and wagers will be the most popular, and adjust their margins accordingly.

Accounting For Variables

A team that enjoys wider support as favourites will have a wider margin than a team that’s less popular. A winning wager on the latter will garner a larger payout for you, but a sports betting site only cares that its books are balanced and that it makes a profit.

Simpler wagers like win/draw/win have fewer variables or fewer chances of an unpredictable outcome. A sports betting site can afford a lower margin on these kinds of bets or lines because the risk is reduced. The lower the margin, the better the value to you, the punter.

Conversely, a bookmaker’s margin is higher the more complex a bet or betting market is in order to control the variable factor and negate the risk.

In the same vein, you’ll find that major sports like football, tennis or golf usually have lower margins of between 2% and 5%. In comparison, more obscure or exotic betting markets or lines will generally have higher margins, even up to 20%. The basis of which is on the same principle – reducing risk and accounting for variables.

You’ll still find excellent exotic wagers, despite the above, that can cultivate fantastic profits, so don’t limit yourself too much.

So, Why are Sports Betting Odds Different From Bookmaker to Bookmaker?

As you’ve seen, a lot of legwork goes into calculating an event’s implied probability. Sports betting sites have their own research teams, algorithms, client base and margins that define what they will ultimately offer.

While the edge or overround is crucial, sports betting sites also have to keep a finger on the pulse of public opinion.

They have to make decisions on all of these factors leading up to, and even during, an event.

Essentially, sports betting sites are competing for your wagers, so their odds have to be competitive, while still remaining realistic.

Three Quick Tips

  1. Take Advantage of Promotions & Sign Up Offers
    You should know by now that the sports betting industry is awash with welcome bonuses and deals. A specific promotion is usually based on markets with higher margins so a gambling site can offer a deal without losing anything.

    Instead of signing up just because, take the opposite view and find a welcome offer that suits your betting needs. You can sign up for as many betting sites as you like – it’s completely legal.
  2. Shop Around
    Now that you’ve signed up for all of those bonuses, you can shop around regularly for an event’s best-value odds. You’ll also have access to weekly promotions that you can use to your advantage too.
  3. Do Your Homework
    You won’t beat the bookies by looking at stats and data. However, you may just find an edge by looking at other things. Scour the internet for the little-known facts about a player before a game. Who knows, you might find a golden nugget of information that you know could affect a match’s outcome.

The Final Word

Now that you’re armed with all of the vital knowledge you need, you can sharpen your skills and refine your betting strategy. If you want to learn more, have a look at our Betting Guide, section or Tips for some more ways to up your game. Remember, nothing is 100% guaranteed, but it doesn’t hurt to give yourself a fighting chance.