Energy Converter
Convert energy between joules, calories, kilowatt-hours, BTU, electronvolts, and more. Essential for nutrition (food calories), electricity bills, thermodynamics, and physics.
Common Energy Conversions
| From | To |
|---|---|
| 1 kJ | 1,000 J |
| 1 kcal (food calorie) | 4,184 J |
| 1 cal | 4.184 J |
| 1 kWh | 3,600,000 J = 3,600 kJ |
| 1 BTU | 1,055.06 J |
| 1 kWh | 3,412.14 BTU |
| 1 kcal | 3.96832 BTU |
| 1 MJ | 1,000 kJ = 277.778 Wh |
| 1 BTU | 0.000293071 kWh |
Energy Unit Definitions
- Joule (J)
- The SI unit of energy = force of 1 N acting over 1 meter.
- Calorie (cal)
- Amount of heat to raise 1 g of water by 1 °C = 4.184 J.
- Kilocalorie (kcal)
- 1,000 calories = 4,184 J. The "food calorie" on nutrition labels.
- Kilowatt-hour (kWh)
- 3.6 MJ. Standard unit on electricity bills.
- BTU
- British Thermal Unit = 1,055.06 J. Used in HVAC and US energy.
Frequently Asked Questions
What is the difference between a calorie and a kilocalorie?
A food calorie (kcal) = 1,000 thermochemical calories. Nutrition labels use kcal but write "Calories" with a capital C.
How many joules are in a kWh?
1 kilowatt-hour = 3,600,000 joules (3.6 MJ).
How do I convert BTU to kWh?
Divide BTU by 3,412.14. Example: 10,000 BTU ÷ 3,412.14 = 2.93 kWh.