π’ Unit Converter
Energy Converter
Free online energy unit converter.
π‘ Tip: Energy is one of the most fundamental quantities in physics. 1 Joule is roughly the energy needed to lift an apple by 1 meter. 1 kWh = 3.6 million Joules β the standard unit for electricity billing.
π Unit Reference Table
| Unit | Conversion to J | Description |
|---|---|---|
| J (Joule) | 1 J = 1 J | SI base energy unit |
| kJ (Kilojoule) | 1 kJ = 1000 J | Kilojoule, food energy label |
| cal (Calorie) | 1 cal = 4.184 J | Calorie, legacy thermal unit |
| kcal (Kilocalorie) | 1 kcal = 4184 J | Kilocalorie, food 'Calories' |
| Wh (Watt-hour) | 1 Wh = 3600 J | Watt-hour, small battery capacity |
| kWh (Kilowatt-hour) | 1 kWh = 3600000 J | Kilowatt-hour, electricity billing |
| eV (Electronvolt) | 1 eV = 1.602176634e-19 J | Electronvolt, particle physics |
| BTU (BTU) | 1 BTU = 1055.05585 J | British Thermal Unit, HVAC |
β FAQ
How many calories in 1 Joule?
1 Joule (J) β 0.239 calories (cal). One calorie is defined as the energy needed to raise 1 gram of water by 1Β°C, equal to 4.184 Joules.
How many Joules in 1 kWh?
1 kWh = 3,600,000 Joules (3.6 MJ). Kilowatt-hour is the common unit for electricity billing β the energy used by a 1 kW appliance running for 1 hour.
What's the difference between calories and kilocalories?
1 kilocalorie (kcal) = 1,000 calories (cal). Food labels typically show kilocalories, often labeled as 'Calories' with a capital C. One apple contains about 50-100 kcal.