Odds Calculator – Free Odds Conversion & Betting Probabilities

We’ve all been there before. You pour over the sports pages or dig online, looking for the best betting opportunities. Odds are given for every possible outcome, and it can look confusing.

If your bookie gives you any grief about how many bets you’ve placed – and they will – maybe it’s time to learn why a betting odds calculator makes your betting easier and why such a tool is key for making educated betting decisions — every time.

How to Use an Odds Converter Calculator

An odds converter calculator is a tool that allows bettors to convert between different odds formats and implied probabilities. It’s helpful as most bookmakers will offer their odds represented in different forms.

To calculate your odds, you first need to set up the converter by supplying the odds for each possible outcome in the “Odds” section. The calculator will then determine how much your winnings would be if you placed a $100 bet on that outcome.

For example, let’s say you want to bet on Manchester United winning against Chelsea (1.42). You would enter 1.42 in the “Manchester United” row, 100 in the “Amount” row, and click on “Calculate” to get your result.

Our free bet conversion calculator takes things one step further. It allows you to convert American odds, fractions, decimals, and implied probabilities into percentages to easily compare them and make better-informed decisions when placing bets.

Why Convert Odds?

While it may seem unnecessary, odds conversion is essential in betting. If you don’t convert your winnings back into units, it can be difficult to tell whether you’re making or losing money over time.

For example, if you are an American Football fan, it would be helpful to know the probability of your team winning the Super Bowl. You could use this calculator and see that they have a 5% chance of winning.

American Odds & Moneyline Calculator

American odds are often used in the United States, Canada, and Australia. Moneyline is the most common, a straight line of numbers against a specific opponent.

The odds calculator at the top of this page can help you convert American Odds (such as a bet offered at -110) into decimal odds and vice versa. You can do this directly on our site by selecting “American” or “Decimal” as the input type.

We also provide a Moneyline bet calculator that shows the maths behind each number so you can understand how it works and why some numbers are bigger than others.

Converting American Odds to Decimals

For positive American odds, divide the value by 100 and add 1. For example, for a +200.00 Moneyline, you would divide $200 by 100 and add 1 to get 3.0.

For negative Moneyline odds, divide 100 by the absolute Moneyline value and add 1. For example, for a -130 Moneyline, you would divide 100 by 130 and add 1 to get 1.769.

Converting American Odds to Fractionals

To convert positive American Odds to Fractionals, divide the value by 100. Alternatively, make the value the denominator if it’s negative. For example, here’s what you get converting +250 and -250 odds into fractional form.

For +250: Fractional Odd = 250/100 = 2.5/1 = 5/2,

For -250: Fractional Odd = 100/250 = 1/ 2.5 = 2/5

Converting American Odds to Implied Probabilities

Say an event has American odds of -250; you can convert this number into implied probability by using the absolute value of odd in the formula:

Implied Probability = American Odd/(American Odd + 100)*100 = 250/(250 + 100) = 71.43%

Implied Odds Calculator

Our calculator does more than just convert money lines and odds; it will also calculate implied odds for you. You can consider implied odds simply the implied probability of a betting outcome expressed as a fraction.

In practice, however, most bookmakers use a different way of calculating their implied odds, which is why it’s easier to use our implied probability calculator to compare different sportsbooks’ numbers without having to do any math yourself.

Converting Implied Odds to Decimals

Converting implied odds to decimals requires only a simple conversion by the following formula:

Decimal odd = 1÷ Implied probability

So if the Los Angeles Lakers have an 80% (0.8) win probability on their next match by your bookmaker, converting that into the more traditional decimal odd would be:

Decimal Odd = 1÷ 0.8 = 1.25

Converting Implied Probabilities to American Odds

Implied probability conversions depend on what side of the halfway divide the value is. When it’s above 50%, say in the case of the LA Lakers above, the conversion formula will be:

– (Implied Probability ÷ (1 – implied probability) )  x  100

= – (0.8 ÷  (1 – 0.8) )  x  100  =  – 400

Alternatively, for a 30% Implied probability conversion:

(Implied Probability ÷ (1 – implied probability) )  x  100

= (0.3 ÷  (1 – 0.3) )  x  100  =  + 42.86

Converting Implied Odds to Fractionals

Converting implied odds to fractional odds is easy. If you had to convert the 80% implied probability of Jerry Rice scoring a touchdown into fractional odds – simply use the formula:

(1/Implied Probability) – 1  =   ( 1/0.8 ) – 1  = ¼

Decimal Odds Calculator

Decimal odds are often used in European betting markets, such as those on our site. If you’re unfamiliar with this method, you will often have to convert the odds into fractional or American odds before placing a bet.

Our decimal odds calculator makes this process simple and displays the math behind each conversion so you can see how each side is calculated.

Converting Decimal to American Odds

The bookmaker defines the number of decimal places in decimal odds. For example, 1.5 and 2.0 are decimal odds, but converting each to American odds is calculated differently. Let’s take a look at a Superbowl game with 1.2 and 2.4 decimal odds in favor of either side.

For decimals above 2.0:  American Odd = (Decimal Odd – 1) x 100 = (2.4 – 1) x 100 =  +140

For decimals below 2.0: -100 ÷ (Decimal Odd -1) = -100) ÷ (1.4-1) = – 250

Converting Decimal Odds to Fractionals

To convert decimal odds to fractionals, simply subtract 1.0 from the decimal odd and divide the result by 1. Here’s a look at a 3.0 decimal odd when converted:

3.4 – 1.0 =  2.4/1 or 12/5

Converting Decimal Odds to Implied Probabilities

The best way to visualize implied probability is by converting the odds into percentages. To do this, simply divide 1.0 by the decimal odds. So, if your odds are 1.50 and you divide 1.0 by 1.50, you’ll get 0.50 which equals 50%.

Fractional Odds Calculator

Fractional odds are simply the ratio between the stake and the payout. For example, if you bet $10 on a horse with odds of 2.00, your expected return is $20. The odds calculator on our page allows you to convert any decimal odds into fractional odds, so you don’t have to do all these steps manually when converting odds between different formats.

Converting Fractional Odds to American Odds

To convert fractional odds above 1.0 to American odds, simply multiply the fractional value by 100. Alternatively, for fractional odds below 1.0, divide the -100 by the fractional value. Here’s a quick example below

For 6/4: American odd = 6/4 x 100 = +150,

For 4/5: American odd = –100 ÷ (4/5) = – 100/ 0.8 = –125

Converting Fractional Odds to Decimals

To convert fractionals to decimal odds, simply convert the fractional odds into decimal form and add 1.0 to get a final value. Here’s a look at a 5/4 decimal odd when converted:

Decimal odd = (5/4 in decimal form) + 1 = 1.25 + 1 = 2.25

Converting Fractional Odds to Implied Probabilities

If you want to do it manually, the formula for converting odds from fractional to implied probability is as follows:

Equation:  Denominator / (numerator+ denominator ) * 100

A 6/4 fractional in Implied probability form will, therefore, = (4 ÷ (6+4)) x 100 = 40%