Kilojoule to Calorie Converter NZ
This converter changes food energy between kilojoules and calories, which is a conversion New Zealanders need more often than most. Under the Australia New Zealand Food Standards Code, the nutrition information panel on packaged food sold here must state energy in kilojoules. Calories may appear as well, but kilojoules are the required unit, which is why a muesli bar in a New Zealand supermarket tells you it has 900 kJ rather than 215 calories. Meanwhile most fitness apps, diet books and online content are written for American audiences and speak entirely in calories, so anyone tracking intake here ends up converting between the two constantly. The relationship is fixed: one nutritional calorie is 4.184 kilojoules. One point worth clearing up is that the calorie used in nutrition is really a kilocalorie, a thousand of the small calories used in physics, and food labelling has simply kept the shorter word. So when a label says 215 Cal and an app says 215 kcal, they mean the same thing. The converter also shows the figure per 100 grams, which is the column that lets you compare two products honestly rather than comparing different serving sizes.
One nutritional calorie (Cal or kcal) is 4.184 kilojoules. New Zealand nutrition panels are required to show kilojoules; calories are optional.
How it works
Energy is converted to kilojoules first, then out again. One nutritional calorie equals 4.184 kilojoules exactly, so kilojoules divided by 4.184 gives calories, and calories multiplied by 4.184 gives kilojoules. The nutritional calorie, written Cal with a capital C or kcal, is one thousand of the small calories used in physics. If you enter a serving size in grams, the calculator scales the figure to 100 grams so you can compare two products on the same basis rather than on whatever serving each manufacturer chose.
Worked example
Take a 40 gram muesli bar labelled 900 kilojoules, the default here. Divide 900 by 4.184 and you get about 215 calories. To compare it against another bar of a different size, scale to 100 grams: 900 divided by 40, times 100, is 2,250 kJ per 100 g, or about 538 calories per 100 g. That per-100-gram figure is the one printed in the second column of a New Zealand nutrition panel, and it is the only fair way to compare two products.
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