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Kilojoules to Calories Converter

Convert kilojoules to food calories instantly, with a reference table for nutrition labels and daily intake.

KJ to Calories Converter

1 kJ = 0.24 kcal

Multiply kilojoules by 0.23900574 to get calories.

The link carries the values you entered, so whoever opens it sees the same result. Nothing is stored on our side — the numbers travel in the link itself.

Kilojoules to calories reference table

The conversions people look up most often, rounded to 2 decimal places.

Common kilojoules to calories conversions
Kilojoule (kJ)Calorie (kcal)
100 kJ23.9 kcal
250 kJ59.75 kcal
500 kJ119.5 kcal
837 kJ200.05 kcal
1,000 kJ239.01 kcal
2,000 kJ478.01 kcal
4,184 kJ1,000 kcal
5,000 kJ1,195.03 kcal
8,400 kJ2,007.65 kcal
8,700 kJ2,079.35 kcal
10,000 kJ2,390.06 kcal
12,000 kJ2,868.07 kcal

The kilojoules people look up most

1,000 kJ = 239.01 kcal
A useful anchor for labels that lead with kilojoules: divide by roughly 4.2 to get calories.
2,180 kJ = 521.03 kcal
A Big Mac, as an Australian menu board would post it - kilojoules first, calories rarely at all.
8,400 kJ = 2,007.65 kcal
The EU reference intake for an average adult, printed alongside the calorie figure on every pack.
8,700 kJ = 2,079.35 kcal
The Australian reference daily intake, which is why 8,700 kJ appears on every food label there.

How the kj to calories calculation works

A food calorie is exactly 4.184 kilojoules:

calories (kcal) = kilojoules ÷ 4.184

The word "calorie" is doing two jobs. The one on a nutrition label is a kilocalorie — 1,000 of the calories a physicist means. A label saying "250 calories" means 250 kcal, or 250,000 small calories. Every figure on this page uses the food calorie, which is what "kcal" and "Cal" both denote.

Which unit a label leads with depends on the country. Australia, New Zealand and much of Europe print kilojoules first; the US, UK and Canada lead with calories. EU labels are required to show both.

Daily intakes, converted:

  • 8,700 kJ → 2,079 kcal — the Australian reference daily intake
  • 8,400 kJ → 2,008 kcal — the EU reference for an average adult
  • 10,000 kJ → 2,390 kcal
  • 2,000 kcal → 8,368 kJ — the US reference value

Everyday foods:

  • A banana, 450 kJ → 108 kcal
  • A slice of bread, 350 kJ → 84 kcal
  • A can of cola, 590 kJ → 141 kcal
  • A Big Mac, 2,180 kJ → 521 kcal

For a quick mental figure, divide kilojoules by 4 and take off 5% — or just divide by 4 and accept a 4.6% overestimate, which is smaller than the error in most portion estimates anyway.

Food energy labels are themselves approximate: US regulations permit up to 20% variance from the stated value.

Frequently asked questions

Is 4.184 the only definition of a calorie?

There are several, all within a fraction of a percent of each other. Nutrition uses the thermochemical calorie of exactly 4.184 joules, fixed by definition. The 15-degree calorie is 4.1855 J and the international steam table calorie 4.1868 J, both derived from measurements of heating water. For food the differences are far smaller than the labelling tolerance, so the thermochemical figure is used throughout.

Do the calories on a label mean what my body absorbs?

They are an estimate of available energy rather than a measurement of heat released. Labels are calculated using Atwater factors - 4 kcal per gram of protein and carbohydrate, 9 for fat and 2 for fibre in the EU - rather than tested food by food. Whole nuts and high-fibre foods are now known to deliver less than those factors predict, because some of the energy passes through undigested.

Does a kilojoule of food equal a kilojoule of work?

Not in the body. Human muscular efficiency is around 20 to 25%, so producing 100 kJ of mechanical work consumes roughly 400 to 500 kJ of food energy and the rest leaves as heat. A cyclist holding 200 watts is doing 720 kJ of work in an hour but burning nearer 3,000 kJ. The unit conversion is exact; the conversion between food and effort is not.

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Further reading