About

Global food trade often leads to confusion regarding energy labels. In Europe and Australia, the primary unit is the Kilojoule (kJ). In the US and UK, the preferred unit is the Kilocalorie (kcal), colloquially referred to as just "Calories". For individuals tracking macronutrients or managing weight, misinterpreting these values can lead to overestimating or underestimating intake by a factor of four.

This tool performs the thermochemical conversion required for nutritional accuracy. It is designed for dietitians, athletes, and anyone navigating imported food labels who needs to normalize their energy data into a single format.

Formulas

The conversion is based on the specific heat capacity of water. The thermochemical definition used in nutrition is:

E_kcal = E_kJ4.184

This means you must divide the Kilojoule value by roughly 4.2 to get the Calorie count.

Reference Data

Food Item (Approx)	Energy (kJ)	Energy (kcal)
Cucumber (100g)	65	15
Apple (Medium)	395	95
Egg (Large)	325	78
Bread Slice	420	100
Banana	440	105
Can of Cola	585	140
Protein Bar	840	200
Avocado (Half)	670	160
Fast Food Burger	2,100	500
Pizza (Slice)	1,200	285
Recommended Intake (F)	8,400	2,000
Recommended Intake (M)	10,500	2,500

Frequently Asked Questions

Yes. In nutritional contexts, the word "Calorie" (with a capital C) actually refers to a Kilocalorie (1,000 small calories). Scientifically, 1 kcal = 1,000 cal, but food labels use them interchangeably.

This is the thermochemical calorie definition, which defines exactly 4.184 Joules as the energy required to raise the temperature of 1 gram of water by 1°C. It is the international standard for food labeling.

Yes. Whether the energy comes from protein, fats, or carbohydrates, the unit conversion between kJ and kcal remains constant.

The Joule is the SI unit for energy. Many countries adopted the metric system fully and thus use kJ. However, the legacy unit "Calorie" remains deeply ingrained in public understanding of nutrition.