Energy Converter
Energy is the capacity to do work. The SI unit is the joule. Nutrition uses calories, electricity bills use kilowatt-hours, and heating and cooling often use BTU. All are different sizes of the same underlying quantity.
1 J = 0.00023900574 kcal
About energy conversion
Energy conversion is commonly needed when nutrition labels, electricity bills, heating, and physics.
Popular conversions
All energy units
| Unit | Symbol | System |
|---|---|---|
| Joule | J | SI |
| Kilojoule | kJ | SI |
| Calorie | cal | Metric |
| Kilocalorie | kcal | Metric |
| Watt-hour | Wh | Metric |
| Kilowatt-hour | kWh | Metric |
| British Thermal Unit | BTU | Imperial |
| Foot-pound | ft·lb | Imperial |
| Electronvolt | eV | Other |
Frequently asked questions
What is the base unit for energy?
Energy conversions on this site are calculated against the joule (J).
Which energy units can I convert?
You can convert between 9 units, including joule, kilojoule, calorie, kilocalorie, and more.
Where is energy conversion useful?
It is commonly needed when nutrition labels, electricity bills, heating, and physics.
Does this converter mix measurement systems?
The converter supports SI, Metric, Imperial, Other units and keeps their exact definitions separate so results stay accurate.