How to convert kilojoules to Calories

Written by Catherine Saxelby on Wednesday, 30 September 2009.
Tagged: Calories, dieting, diets, energy, fat loss, food labels, FSANZ, guides, kilojoules, nutrients, nutrition, technology

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Just like yards became metres and pounds became grams, so Calories have become kilojoules. Kilojoules are the metric equivalent of Calories and have replaced Calories in Australia and many other metric countries. Yet they're very confusing, especially to my US visitors who have always only known Calories (lucky for me, I grew up with Calories then had to learn kilojoules!)

These are the units used to measure food energy - kilojoules (abbreviated to kJ) and Calories (Cals). Like other food scientists, I use the capital C as shorthand for the longer correct term of kilocalories.

Kilojoules LOOK four times larger than Calories simply because there are more digits eg a bowl of cereal supplies around 480 kilojoules or 117 Calories.

Conversion is 4.2 ... or just 4

1 Calorie equals 4.186 kilojoules (4.2 or simply 4 is close enough for a quick conversion).
For example, a slice of bread supplies 290 kilojoules or (290 divided by 4) 70 Calories.

Kilojoules are difficult to grasp if you don't have a feel for the numbers. So here's a handy guide to make things more ‘friendly'.

**How diets compare in kilojoules and Calories**
*kilojoules kJ*	*Calories Cals*	*Intake or level*
10000	2400	Typical level of intake of most teenagers
8700	2070	Average intake used to calculate %DI on food labels
7500	1800	Typical weight loss level for a moderately-active man
7000	1650	Typical weight loss level for a sedentary man
6000	1500	Typical weight loss level for a moderately-active woman
5000	1200	Typical weight loss level for a sedentary woman
4000	1000	Supervised fast or meal replacement intake - too low for normal living and activity

Here's how food compares in kilojoules and Calories:


*Food*	*Amount*	*grams*	kJ	*Cals*
Bread	1 slice	30 g	290	70
Egg	1 large	60 g	335	80
Canned salmon, drained	1 can	150 g	525	125
Tim Tam chocolate biscuits	2	38 g	840	200
Krispy Kreme doughnuts, original glazed	2	104 g	1680	400
Orange juice	1 glass	250 mL	400	95

orange-juice-smll 1 glass orange juice = 400 kJ or 95 Calories

Tip

Round the kilojoules to the nearest 0 or 5. So 288 kJ rounds up to 290 kJ, while 292 rounds down to 290 kJ. Five kilojoules translates to 1 Calorie which is hardly anything and makes your useage of kilojoules easier - as there's fewer digits to remember. We round off all the kilojoule counts on our recipes for ease of use.