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
Kilojoule to Kilocalorie — Conversion Table
| Kilojoule (kJ) | Kilocalorie (kcal) |
|---|---|
| 1 kJ | 0.23901 kcal |
| 100 kJ | 23.9006 kcal |
| 1,000 kJ | 239.006 kcal |
| 3,600 kJ | 860.421 kcal |
| 10,000 kJ | 2,390.057 kcal |
| 100,000 kJ | 23,900.574 kcal |
| 1,000,000 kJ | 239,005.736 kcal |
| 3,600,000 kJ | 860,420.65 kcal |
Last updated: July 27, 2026 · Calculated using SI-validated constants (NIST)
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).