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Frequently Asked Questions — kJ/kg to kcal/kg

Question: How many kcal/kg is 1 kJ/kg?

Answer: 1 kJ/kg = 0.2388458966 kcal (IT)/kg. Divide kilojoules per kilogram by 4.1868 to get kilocalories per kilogram.

Question: How do I convert kJ/kg to kcal/kg?

Answer: Multiply the value in kJ/kg by 0.2388458966. For example, 4186.8 kJ/kg × 0.2388458966 = 1000 kcal/kg.

Question: How many kcal/kg is 44,000 kJ/kg (gasoline)?

Answer: 44,000 × 0.2388458966 ≈ 10,509 kcal/kg. Gasoline has a heating value of about 44 MJ/kg, which equals roughly 10,500 kcal/kg.

Question: What is kcal/kg used for in food science?

Answer: In food science, kcal/kg describes the energy density of ingredients. 1 kcal/kg = 1 calorie per gram. Fat ≈ 9000 kcal/kg (37.6 kJ/g), carbohydrates ≈ 4000 kcal/kg (16.7 kJ/g), protein ≈ 4000 kcal/kg (16.7 kJ/g).

Question: How does kJ/kg relate to MJ/kg?

Answer: 1 MJ/kg = 1000 kJ/kg. For context: natural gas ≈ 55 MJ/kg = 55,000 kJ/kg = 13,136 kcal/kg. Converting kJ/kg to kcal/kg: divide by 4.1868.