What is the difference between a kilojoule and a calorie and why, for the love of moderation and balanced diets, can’t we all agree to choose one and stick to it?

After all, when we talk about Calories (Cal) and kilojoules (kJ), we are talking about exactly the same thing – both are a measure of the energy provided by foods and drinks.  

As a side note when we talk about Calories, we’re actually talking about kilocalories. It seems we just got lazy over the years and somehow dropped the ‘kilo’ part of the word.

Which Countries Count Kilojoules?

You might be surprised to know that nearly every country on the planet officially uses kilojoules. Whilst New Zealand switched over to the metric system, and thus from using calories to kilojoules, confusion still abounds.

It’s likely that the main reason we still hear about calories is because it’s the measure the U.S. and U.K. still use and given their dominance in popular culture, it’s a term we find difficult to escape in New Zealand.

What’s the Difference Between Calories and Kilojoules?

Not much really is the simple answer. Like the mile to the kilometre, they are measuring exactly the same thing.

But to help you do your calculations here is the simple equation.

1 Calorie = 4.18 kilojoules

Or

1 kilojoule = 0.24 Calories (about ¼)

So to convert Calories to kilojoules, multiply the number of Calories by 4.

And to convert kilojoules to Calories, divide the number of kilojoules by 4.

On all Coca-Cola products (except for water as it doesn’t contain kJs), the number of kilojoules in each product is clearly marked on the front of pack to help you keep track and in control of your kilojoule intake.  For those who still work in calories, we also provide Calorie information in the nutrition information panel.

In New Zealand, recommendations for daily intake of energy are based on an 8700 kJ requirement because this has been determined to be the average New Zealand adult’s daily energy needs.

However, the number of kilojoules needed every day to maintain a healthy weight depends on factors such as your age, height, sex and level of physical activity.

If you would like more information about healthy weight, or if you’re concerned that you’re under or overweight, please consult a qualified practicing dietitian or doctor.