Energy Converter
Convert energy between joules, calories, kilocalories, kilowatt-hours, BTU, and electron volts. Useful for physics, nutrition, and engineering calculations.
Joules (J)
3600000
Kilojoules (kJ)
3600
Calorie (cal)
860420.65
Kilocalorie (kcal)
860.42065
Watt-hour (Wh)
1000
Kilowatt-hour (kWh)
1
BTU
3412.1416
Electron-volt (eV)
2.2469433e+25
How to use the energy converter
Energy units span 38 orders of magnitude — from eV (atomic) to GJ (industrial).
Formula & explanation
Linear scaling through joules.
Examples
1 kWh = 3.6 MJ ≈ 860 kcal.
Frequently asked questions
- What is the difference between a calorie and a kilocalorie?
- 1 kilocalorie (kcal) equals 1,000 small calories (cal). Food labels use kcal, often written as 'Cal' (capital C) or simply 'calories' in everyday speech.
- How many joules are in a kilowatt-hour?
- 1 kilowatt-hour (kWh) equals 3,600,000 joules (3.6 MJ).
- What is a BTU?
- A BTU (British Thermal Unit) is the energy needed to raise 1 pound of water by 1°F. 1 BTU ≈ 1055 joules. It is commonly used for air conditioner and heater ratings.
- How do I convert kcal to kJ?
- Multiply kcal by 4.184. For example, 500 kcal × 4.184 = 2,092 kJ.
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