How to Convert kJ to Calories

The exact factor is 4.184 kJ per calorie (FAO, WHO and UNU, Human energy requirements). Some Australian sources round it to 4.18 (Eat for Health) or 4.2 (healthdirect) for simpler sums, so their figures can differ from this converter by a few calories.

The "calorie" on an app or an overseas label is a kilocalorie (kcal), the same unit this converter uses.

Common kJ to Calorie Values

Calories in the table are kilojoules divided by 4.184, rounded to the nearest whole number. The 8,700 kJ row is the average adult daily need that healthdirect gives, and actual needs vary with age, sex, height, weight, muscle and how active you are.

Reading kJ on Australian Food Labels

Nutrition information panels in Australia show energy in kilojoules, and some show kilocalories as well. The panel gives the average amount per serve and per 100 g, or per 100 mL for drinks. The food maker sets the serve size, and it varies between products (Food Standards Australia New Zealand), so it is worth comparing it with the amount you eat.

As a rough guide, it helps to limit high energy foods, such as those with more than 600 kJ per serve (see how to read food labels).

Kilojoules Are Only Part of the Picture

Two foods can carry the same kilojoules but very different nutrition: a large salad and a small block of chocolate are one example healthdirect gives. A healthy diet draws on a wide variety of nutritious foods from the five food groups every day, and plenty of water (Eat for Health).

Regular physical activity is part of the picture too. Australian guidelines suggest adults are active most days, with 30 minutes or more of moderate to vigorous physical activity on most days and muscle-strengthening activities on 2 or more days a week (Department of Health).

If you are working on your weight, these guides go further: what a calorie deficit is and how to calculate yours, how many calories a day to lose weight and how to work out your macros for weight loss. For personal advice about your energy needs or your weight, speak with your GP, an accredited practising dietitian or another registered health practitioner.

Frequently Asked Questions

Does 1 kJ equal 1 calorie?

No. A kilojoule is a much smaller unit than a calorie. One calorie (kilocalorie) equals 4.184 kJ, so 1 kJ is about 0.24 calories. That is why the kilojoule figure on an Australian food label is about four times the calorie figure for the same food.

How many calories are in 1,000 kJ?

There are about 239 calories in 1,000 kJ. The sum is 1,000 divided by 4.184. If you use the rounded factor of 4.2 that some Australian sources use, you get about 238 calories instead. The difference is small for everyday food choices, and either figure works for comparing labels.

How much is 2,000 calories in kJ?

2,000 calories is about 8,368 kJ. To get kilojoules, multiply the calories by 4.184. Australian food labels and health sources use kilojoules, so this is the figure to compare against them. Daily energy needs vary between individuals, depending on age, sex, height, weight, muscle and activity.

How do I convert kilojoules to calories in Australia?

Divide the kilojoules by 4.184, or use the converter at the top of this page. Australian nutrition information panels list energy in kilojoules per 100 g or 100 mL, and some also show calories. Check the serve size on the label too, because the serve the manufacturer lists may differ from the amount you eat.

Is 4,000 kJ a day enough?

4,000 kJ is about 956 calories a day. That is below 5,000 kJ (about 1,200 calories), the daily intake that a good weight management service advises against going under, according to the Better Health Channel. Energy needs vary between individuals, so speak with your GP or a dietitian before eating much less than usual.

References

• FAO, WHO and UNU (2004). Human energy requirements: introduction (energy units).
• Better Health Channel. Weight management services.
• healthdirect. Kilojoules.
• healthdirect. How to read food labels.
• Food Standards Australia New Zealand. Nutrition information panels.
• Eat for Health (NHMRC). Australian Dietary Guidelines 1 to 5.
• Eat for Health (NHMRC). Nutrient Reference Values: dietary energy.
• Department of Health, Disability and Ageing. Physical activity and exercise guidelines for adults (18 to 64 years).

This page is general information only, and outcomes vary between individuals. Speak with a registered Australian healthcare practitioner for advice about your own health.