kilokalorie

Kilocalorie, abbreviated kcal, is a unit of energy equal to 1,000 small calories. It is commonly used in nutrition to measure the energy content of foods. In nutrition, the term Calorie (capital C) is often used on labels and equals one kilocalorie.

One kilocalorie equals 4,184 joules (J) or 4.184 kilojoules (kJ). Because of this, energy values can be converted between kilocalories and kilojoules by multiplying or dividing by 4.184.

Historically, the calorie was defined as the amount of heat needed to raise the temperature of 1 gram of water by 1°C at one atmosphere. The kilocalorie is 1,000 calories, and the nutrition Calorie is the kilocalorie.

Today the SI unit for energy is the joule, but kcal remains widely used in dietary contexts. Food labels may present energy in kcal or kJ depending on the country.

Kilocalorie remains a practical unit for expressing dietary energy and energy balance, even as scientific work increasingly uses joules.