Energy Converter
Convert between 10 units of energy — joules, kilojoules, megajoules, calories, kilocalories, watt-hours, kilowatt-hours, BTU, electronvolts, and foot-pounds.
About the Energy Converter
Energy is the capacity to do work, measured in joules (J) in the SI system. Different fields use their own preferred units: food science uses kilocalories (kcal), electricity billing uses kilowatt-hours (kWh), and atomic physics uses electronvolts (eV). Understanding energy unit conversions is fundamental to physics, engineering, nutrition, and environmental science.
- ›One kilowatt-hour (kWh) equals 3,600,000 joules (3.6 MJ)
- ›A dietary Calorie (kcal) equals 4,184 joules
- ›The atomic bomb dropped on Hiroshima released ~6.3 × 10¹³ joules of energy
- ›The energy in one litre of petrol is approximately 34.2 MJ
Frequently Asked Questions
What units does the Energy Converter support?
The Energy Converter supports multiple units with instant conversion. Convert between 10 units of energy — joules, kilojoules, megajoules, calories, kilocalories, watt-hours, kilowatt-hours, BTU, electronvolts, and foot-pounds. All results use SI-validated constants accurate to 8 significant figures.
Is this Energy Converter free?
Yes — completely free. No registration, no limits. Works on all devices including mobile.
How accurate is this converter?
Accurate to 8 significant figures using precise mathematical constants validated against international SI standards (NIST and ISO 80000).