Energy Converter
Convert between joules, kilojoules, calories, kilocalories, watt-hours, kilowatt-hours, BTU, and electronvolts. Used in physics, nutrition, and electrical engineering.
1 Joule (J) = 0.001 Kilojoule (kJ)
1 Joule (J) in all units
| Unit | Value |
|---|---|
| Joule (J)input | 1 |
| Kilojoule (kJ) | 0.001 |
| Calorie (cal) | 0.2390057361 |
| Kilocalorie (kcal) | 0.0002390057361 |
| Watt-hour (Wh) | 0.0002777777778 |
| kWh | 2.777778e-7 |
| BTU | 0.0009478133945 |
| Electronvolt (eV) | 6.242197e+18 |
How to Use the Energy Converter
- 1
Select the energy unit you want to convert FROM (e.g. kWh).
- 2
Enter the numeric value.
- 3
Select the unit you want to convert TO (e.g. joules).
- 4
The result appears instantly.
- 5
Use the ⇄ swap button to reverse.
- 6
See all units in the table below.
Energy Conversion Formulas
1 kJ = 1,000 J
1 kcal = 4,184 J
1 Wh = 3,600 J
1 kWh = 3,600,000 J
1 BTU = 1,055.06 J
1 eV = 1.602 × 10⁻¹⁹ JFrequently Asked Questions
What is the difference between a calorie and a kilocalorie?
1 kilocalorie (kcal) = 1,000 calories (cal). Food 'Calories' (with capital C) are actually kilocalories. 1 kcal = 4,184 J.
How many joules in a kWh?
1 kWh = 3,600,000 joules (3.6 MJ). This is the standard unit on electricity bills.
What is a BTU?
BTU (British Thermal Unit) = 1,055.06 J. It is the energy needed to raise 1 pound of water by 1°F. Used in HVAC and heating systems.
What is an electronvolt?
1 eV = 1.602 × 10⁻¹⁹ J. It is the energy gained by an electron moving through 1 volt. Used in atomic and particle physics.