Energy Converter
Convert between joules, kilojoules, BTU, calories, kilocalories, kilowatt-hours, and electronvolts with our free online energy conversion calculators.
Energy Converters
- Joules to Kilojoules
- Joules to BTU
- Joules to Calories
- Joules to kcal
- Joules to kWh
- Joules to eV
- kJ to Joules
- kJ to BTU
- kJ to Calories
- kJ to kcal
- BTU to kJ
- BTU to Joules
- BTU to kWh
- kWh to BTU
- kWh to Joules
- Calories to Joules
- Calories to kJ
- Calories to kcal
- kcal to Calories
- kcal to Joules
- kcal to kJ
- eV to Joules
- eV to keV
- eV to MeV
- eV to GeV
- keV to eV
- MeV to eV
- GeV to eV
Energy Units
Joule (J) — The SI unit of energy. 1 J = 1 kg·m²/s².
Kilojoule (kJ) — 1 kJ = 1000 J. Used in food energy and thermodynamics.
BTU (British Thermal Unit) — 1 BTU = 1055.06 J. Common in HVAC and US energy systems.
Calorie (cal) — 1 cal = 4.184 J. The energy to raise 1 g of water by 1°C.
Kilocalorie (kcal) — 1 kcal = 4184 J. The "Calorie" used in nutrition labels.
Kilowatt-hour (kWh) — 1 kWh = 3,600,000 J. Standard unit for electrical energy billing.
Electronvolt (eV) — 1 eV = 1.602 × 10⁻¹⁹ J. Used in particle and atomic physics.