Esports Betting / Betting Calculators / Odds Calculator

Odds Calculator

Sports Writer

Last Updated on 07/01/2026

Fact checked by: Mike McKean

Based on my experience, betting odds can be pretty complicated. In my quest to make sense of those really confusing numbers, I came across a betting odds calculator, a tool for converting and interpreting betting odds.

To use one, I simply enter my stake and the odds from my bookmaker as input. In return, the calculator outputs relevant information to my selections by interpreting the odds. In this guide, I’ll discuss betting odds, how an odds calculator works, and how to use this helpful tool.

Use of our free odds calculator before making your sports bets

Table of Contents

How to use a betting odds calculator
Betting odds explained
Why should I use a betting odds calculator?
What other betting calculators are available?
Conclusion - Odds calculation just got easy
Odds calculator FAQs

How to use a betting odds calculator

You can use an odds calculator to work out the potential returns of a single bet, but you’ll be using it more often with accumulators. A sports betting odds calculator can take input in the form of your stake and the odds for each selection and output your potential returns, the implied probability of the bet winning or losing, among other relevant information.

Before going further into how the calculator works, here’s a quick guide on how to use the average betting odds calculator:

Open the website or app on your device.
Select your bet type (single bet or accumulator).
Enter your bet amount and the odds on the bookmaker’s website in the relevant fields. You may have to enter the odds separately for each selection for parlay bets.
Click on the ‘Calculate’ button and get your results.

If you’re struggling to understand some of the terminologies from my guide above, don’t fret. Here’s a quick explanation of all you may be required to enter when using an odds calculator:

Stake/wager: Your stake is how much you’re betting on the event for a potential reward. You determine your stake based on your risk assessment and tolerance and, if applicable, according to your bankroll strategy.
Accumulator/parlay: You’ll usually see two bet types on a sports betting odds calculator: single and accumulator/parlay. For the former, you’re making a single selection with an outcome dependent on the odds of one event. Conversely, the latter involves more than one selection, so you’ll need to enter the odds separately to calculate the outcome.
Odds: Unlike the wager, the bookmaker calculates and provides the odds; you simply copy them and paste them into your free odds calculator.

Once you’ve entered the necessary information, the betting odds calculator should reveal relevant information about your selections. Here are the most common outputs I’ve seen from popular odds calculators:

Returns/profit: While I often use an odds payout calculator to determine how much I stand to win from a selection, the returns/profit section of an odds calculator also shows you that. The “profit” is how much you’ll make from winning a selection, while “return” is the sum of your potential profit and stake.
Implied probability: Implied probability is a conversion of your regular fractional or decimal odds to mathematical probability. Most odds calculators calculate it by default and display the number once you enter the fractional or decimal odds.

The implied probability of a selection directly correlates with the odds, making it possible for betting calculators to determine them easily and consistently.

You should also expect to see the equivalent of your betting odds in decimal, moneyline, and fractional formats, as most odds calculators will automatically populate them once you enter the odds in one way. So, if you’re looking for a way to convert betting odds from one form to another, betting calculators are also excellent.

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Odds calculator example

Suppose I’m creating a $100 bet slip in basketball at a random sportsbook with the following selections:

Boston Celtics to win vs Dallas Mavericks (2.12 odds).
Al Ittihad Alexandria to win vs Al Ahly (4.00 odds)
Over 210.5 points on the Mavericks vs Celtics game (1.85 odds)

With lots of confusing numbers on my bet slip, I turned to a sports betting odds calculator to help make sense of the numbers. So, I fired one up, entered the fractional odds and the stake, and got the following result:

Odds (Decimal)	Odds (Fractional)	Odds (Moneyline)	Implied Probability
2.12	28/25	+112	47.17%
4.00	3/1	+300	25%
1.85	17/20	-117	54.05%

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Betting odds explained

Betting odds are simply the bookmaker’s best attempt at predicting the likelihood of an event happening. Before the occurrence of an event, say a football match or a horse race, for example, the bookmaker calculates the odds to show the ratio between your stake and your potential winnings.

Betting odds come in three common formats: decimal, fractional, and moneyline. Decimal and fractional odds are easy to understand and are the most common odds outside the United States. In contrast, moneyline or American odds are more common on sportsbooks operating within the States.

Calculating decimal odds is pretty simple. Firstly, you add your stake to your potential winnings and find the ratio of the sum to your stake. Converting your result to decimal form will result in the decimal odds for your bet. For example, if your stake is $5 and you stand to win $10, the decimal odd for the selection would be 3.0.

Fractional odds are slightly simpler; they’re the ratio of potential winnings to stake. In my hypothetical scenario from above, the fractional odd would be 2/1, as you don’t have to factor in your stake for this odd format.

Lastly, moneyline or American odds simply illustrate how much you’d win if you bet $100 on the given selection and won. Also, you don’t add your stake to your potential winnings when calculating moneyline odds.

Negative moneyline odds show how much you need to stake to win $100.

Why should I use a betting odds calculator?

Having an odds calculator handy is not simply useful as a bettor, it’s indispensable. Here are a couple of reasons why you need a calculator if you struggle with betting odds:

Facilitates convenient conversions and calculations

Betting odds tell you a lot about your selections, from the winning probability to your potential returns for specific wagers. While you can manually calculate all that information by hand, using a betting calculator makes the calculations simpler and more convenient.

Odds calculators are also great for converting odds from one form to another. A fair odds calculator will automatically convert your odds from fractional to decimal and moneyline and vice versa once you enter them, allowing for seamless conversions.

It saves you time

Betting odds don’t always come in beautiful, round, whole numbers. When they come in complicated fractions or decimals, you may struggle to calculate the potential return for a particular wager by hand. On the other hand, a betting odds calculator simplifies the process, eliminating human error while completing the task quicker than you can think.

Facilitates arbitrage

Sometimes, you can get better betting opportunities by comparing odds across different bookmakers. If the potential winnings on opposite possibilities cancel themselves out, you can smartly hedge yourself against losses using arbitrage. Calculating arbitrage betting opportunities by hand isn't easy, but an arbitrage betting calculator makes it simple.

Essential for the Kelly Criterion strategy

The Kelly Criterion is a popular betting strategy that determines the optimal wager for particular selections using their win probabilities. Invented by John Kelly in the 1950s, the strategy involves betting more on games likely to win and less on those likely to lose.

While you can manually use the strategy by calculating your bet sizes on pen and paper, using a Kelly Criterion betting calculator is significantly better.

What other betting calculators are available?

Betting calculators come in different forms, with the odds calculator only being one of them. Here are other betting calculators on this website and how they can help you become a better sports bettor.

Calculator	Use
ROI Calculator	Calculates the potential return on investment from winning a bet.
Arbitrage Betting Calculator	Determines how much to stake on different bets to make a profit or breakeven.
Kelly Criterion Betting Calculator	Calculates the optimal bet size to take advantage of the difference between true and implied odds of a selection.
Fair Odds Calculator	Compares market odds to determine a fair odd for a specific selection.
Tricast Calculator	Computes potential payout from predicting the top three finishers of a horse race.

Conclusion - Odds calculation just got easy

Odds are the lifeblood of betting that all effective bettors must understand. If you struggle to make sense of betting odds, a fair odds calculator can help with no calculations required on your part.

To use one, simply enter your stake and the odds in any format and watch the calculator come up with essential information and insights about your selections.

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Odds calculator FAQs

❓ How do I calculate betting odds probability?

Betting odds probability correlates directly with the implied probability of an event. You can calculate the implied probability by entering the odds in an odds calculator.

💰 What is the formula for betting odds payout?

The formula depends on the odds type. However, you can bypass using a complex formula by simply entering the odds and your stake into a betting odds payout calculator to get your potential return automatically.

🧮 Who calculates betting odds?

The bookmaker calculates the betting odds based on their perception of the likelihood of the event happening, otherwise called the “implied probability.” The implied probability always directly correlates with the odds, which is also proportional to the potential payout.