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Frequently Asked Questions — J to cal

Question: How do you convert joules to calories?

Answer: Divide by 4.184. For example, 100 J divided by 4.184 = 23.9 cal.

Question: How many calories is 100 joules?

Answer: 100 divided by 4.184 equals approximately 23.9 calories (thermochemical).

Question: How many calories is 1,000 joules (1 kJ)?

Answer: 1,000 divided by 4.184 equals approximately 239 cal = 0.239 kcal.

Question: How many calories is 4,184 joules?

Answer: 4,184 divided by 4.184 = exactly 1,000 cal = 1 kcal. This reflects the definition of the thermochemical kilocalorie.

Question: What is the difference between joules and calories?

Answer: Joules are the SI unit used in physics and engineering. Calories are a traditional unit used in chemistry and nutrition. 1 cal = 4.184 J. For food energy, kilocalories (kcal) are standard.