Energy Converter
Convert energy units: J, kJ, kcal, cal, kWh, BTU, and eV
Full Energy Conversion Table
Joule (J)
4,184
Kilojoule (kJ)
4.184
Calorie (cal)
1,000
Kilocalorie (kcal)
1
Kilowatt-hour (kWh)
0.001162222222
BTU (BTU)
3.965651243
Electronvolt (eV)
2.611442e+22
How to Convert Energy
Enter the energy value and select units. Instantly calculates kcal↔kJ, J↔cal, and more.
What are kcal, kJ, and J?
Joule (J) is the SI energy unit. 1 calorie (cal) = 4.184 J, 1 kilocalorie (kcal) = 4,184 J, 1 kWh = 3,600,000 J.
Frequently Asked Questions
How many kJ is 1 kcal?
1 kilocalorie (kcal) is approximately 4.184 kilojoules (kJ).
What is the difference between food calories and scientific calories?
Food 'calories' are actually kilocalories (kcal). In science, 1 cal = 4.184 J; on food labels, 1 Cal = 1 kcal = 4,184 J.
How many joules (J) is 1 kWh?
1 kilowatt-hour (kWh) is 3,600,000 joules (3.6 MJ).
What is BTU?
BTU (British Thermal Unit) is used mainly for air conditioning and heating capacity. 1 BTU ≈ 1,055 J.
How do I convert exercise calories burned to joules (J)?
1 kcal (food calorie) = 4,184 J. For example, 100 kcal = 418,400 J.