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Betting Odds Explained: Your Ultimate Guide

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Betting has always been a game of numbers and luck, sometimes one more than the other, but punters can only hope for the odds to tip to their favored outcomes and predictions. Even then, there’s still a method to the chaos the games of chance and betting bring, from traditional sports betting to casino games, card games, and even virtual games.

Betting odds are a way to express the likelihood of a specific outcome in a sporting event. Understanding how to read betting odds is crucial for anyone interested in sports betting. Read on to learn more about how understanding the math behind the odds can help you make more informed betting decisions, and more importantly – safe ones.

You will learn how to read, understand and convert the different odds types – American odds, Decimal, and Fractional. There’s also a notable difference between true odds and bookmaker odds – something we’ll also cover. If you’re eager to get to the gist of it, feel free to read our specially curated quicktake.

betting odds explained

What are Betting Odds and How To Calculate Them

Each time you think about placing a bet, you are most likely going to ask yourself  “What are the chances?”, and calculating the odds can provide you with a statistically relevant answer. Odds are essentially a numerical representation of how likely an event is to occur—the essence of gambling strategy. 

True Odds vs. Bookmaker Odds

True odds represent pure mathematical truth – an absolute value of an outcome without any external influences. In contrast, bookmaker odds take into account a margin that ensures the house’s profitability. Finding the middle value and taking into account the differences can be the subtle, but valuable advantage to place successful wagers.

While true odds provide a baseline for what might statistically occur, bookmaker odds are the actual terms of the gambling agreement. Recognizing that these odds often incorporate a premium for the bookmaker – something that can affect a bet’s value – is pivotal. Experienced bettors learn to identify when bookmaker odds offer an opportunity, a moment where the potential payout overshadows the risk, making the right bet.

bookmaker odds

Types of Betting Odds

Types of betting odds differ tremendously across countries, and continents in fact, with each system having its origins deeply rooted in the historical context of the evolution of sports and gambling.

It also points out the different measure systems between countries, such as with miles vs. kilometers, or pounds vs. kilograms.

American Odds

American odds use plus (+) and minus (-) signs to represent the odds. Positive odds (e.g., +200) show how much profit you can make on a £100 bet, while negative odds (e.g., -150) indicate how much you need to bet to win £100. This system is commonly used in the United States but applies to various sports worldwide. Positive odds suggest higher potential profits with lower chances of winning, whereas negative odds indicate a higher probability of winning with smaller returns.

  • Positive Moneyline: Shows the profit on a £100 bet.
    • Example: +500 means if you bet £100, you win £500 plus your £100 stake, totaling £600.
  • Negative Moneyline: Shows how much you need to bet to win £100.
    • Example: -200 means you need to bet £200 to win £100 plus your £200 stake, totaling £300.

Decimal Odds

Decimal odds, widely used in Europe, Australia, and Canada, show the total payout from a bet as a single decimal number. To find the total return, you multiply the decimal odds by the stake. This system includes both the initial wager and the profit.

  • Calculation: Multiply the decimal odds by the stake.
    • Example: For 2.50 odds, if you bet £10, the total payout is £25.
    • To determine just the profit, subtract one from the decimal odds.

Fractional Odds

Fractional odds, commonly used in the UK and Ireland, are presented as fractions (e.g., 5/2 or 7/4). The left number represents the profit, while the right number is the stake. This system is traditional in horse racing and sports betting, providing a clear view of potential profits based on the wager amount.

  • Calculation: If you bet 1 unit, you win the numerator (left number) in units plus your original stake.
    • Example: For 5/1 odds, if you bet £10, you win £50 plus your £10 stake, totaling £60.

Tools for Calculating Betting Odds

Calculating betting odds is not that difficult once you understand the conversion formulae and fundamentals of chance and implied probability. However, most bettors are going to look for a quick way to convert the different types of odds if they need to, or to build more favorable odds for their bets. Luckily, there are many betting odds calculators, odds converters, and bet builders online that you can find and use on our site.

Bet builders and calculators

Bet calculators offer a method to swiftly determine potential payouts. By taking into account variables like bet type, odds, stake, promotions, bet calculators provide you with the potential results of your bet, showing how much you could win or lose.

Most bet calculators follow the same format, and here is a step-by-step guide to using bet calculators:

  1. Select the bet type.
  2. Enter the stake.
  3. Choose the odds format.
  4. Add the odds for each selection.

By following these steps, you can calculate the outcome for your wagers, even for the most complex bets.

Odds Conversion Chart

You can also look at odds conversion charts to compare the odds, but you can easily find a calculator that does the same thing. The table below shows how fractional, decimal, and american odds convert, and the implied probability.

FractionDecimalAmerican (Moneyline)Implied Probability

You can also explore our page where you will read about best sports betting sites with the best odds in UK.

Practical Tips for Bettors

The most valuable advice you can get for success in betting is to stay humble and play for the long run. Contrary to popular belief, betting is a game of patience and lucky strikes of chance, which you might tip to your favor by learning more about the type of betting you are taking part in. Either way, we’ll provide you with some useful betting strategies and risks that you should be aware of before placing a bet.

Betting strategies that you can consider

Bankroll Management

Setting a budget and sticking to it will help avoid significant financial losses while saving for better chances of winning.

Parlay Bets

You could also use Parlay Bets to combine multiple bets into one wager, where all individual bets must win for the parlay to payout. This increases the potential payout but also the risk, since all your individual wagers have to win in order to score the largest possible payout.

Game selection

Betting on sports matches is not the same as betting on eSports, virtual games, or placing roulette and blackjack bets. If you want to maximize your chances of winning, you need to do some research on how the odds work for that specific game and bet.

Common Betting Mistakes to Avoid

Most common mistakes in betting and gambling in general, are actually of psychological nature. Please, if you notice any of the following behavior while you’re playing, make sure to take a step back, and read more about our Safer Gambling tips that you will find in the navigation menu and seek help if needed.

Gambler’s Fallacy

The paradoxical and mistaken belief that past events influence future probabilities in independent events, such as thinking a coin is due to land on heads after several tails or chasing black on roulette after a long series of reds. 


Being overconfident in your ability to predict outcomes on bets and wagers due to your subjective feelings can lead to placing high-risk bets and huge losses. Make sure to think well before placing your bets.

Our final thoughts about betting odds

Understanding betting odds—whether American, decimal, or fractional—is crucial as they represent both the probability of an event and potential payout, forming the basis of successful betting strategies, but at the end of the day, there is no guarantee that you will actually win. 

In order to minimize potential losses, you need to be aware of the risks involved in gambling and avoid “chasing luck” in attempts to make a comeback. 

Make sure you make informed decisions when choosing your teams or games that you want to bet on, sticking with the lower risk options.

True odds reflect the pure probability of an event, while bookmaker odds include a margin to ensure the bookmaker’s profit. Recognizing and exploiting the differences can enhance bet value.

Calculating implied probability from different types of odds (American, decimal, fractional) allows bettors to comprehend the likelihood of outcomes, aiding in making informed betting decisions.

Frequently Asked Questions

Betting odds are numerical representations that reflect the probability of an event occurring and help determine the potential return on a winning bet. They can be presented in different formats, such as American, decimal, or fractional.

This is the Fractional type of odds, meaning that you would win £7 for waging a £5 stake.

This one type of the American odds – negative moneyline. It means that you’d have to place a £750 bet in order to win £100.

Bookmaker odds are adjusted to include a margin for profit, while true odds represent the real probability of an event occurring without any adjustments. This allows bookmakers to make money from the bets placed.

Implied probability is important because it helps bettors make more informed decisions about their bets by assessing the value of the odds on offer, which are derived from betting odds and represent the bookmaker’s estimation of the likelihood of an outcome.