Converter hub
Energy Converter
Energy conversions cover nutrition, electricity and heating. The calorie here is the small calorie (4.184 J); the food Calorie (kcal) is 1,000 of them. Pick a pair below or open the page for the exact factor, a worked example and a full chart.
Units in this category
Energy conversions cover nutrition, electricity and heating. The calorie here is the small calorie (4.184 J); the food Calorie (kcal) is 1,000 of them.
| Unit | Symbol | Definition |
|---|---|---|
| Joules | J | The joule is the SI unit of energy, equal to one newton-metre. |
| Kilojoules | kJ | A kilojoule is 1,000 joules and appears on nutrition labels in many countries. |
| Calories | cal | The small calorie is 4.184 joules; the food Calorie is a kilocalorie. |
| Kilocalories | kcal | A kilocalorie is 4,184 joules and is the Calorie printed on food labels. |
| Kilowatt-hours | kWh | A kilowatt-hour is 3.6 megajoules and is the unit on electricity bills. |
| British Thermal Units | BTU | The international table BTU is about 1,055.06 joules, used in heating and cooling. |
All energy conversions
Every listed pair has its own page with the formula, examples and a chart. Choose the starting unit:
Calories (cal)
Kilocalories (kcal)
Kilowatt-hours (kWh)
British Thermal Units (BTU)
Frequently asked questions
How many energy units are supported?
6 units, which gives 8 one-way conversions.
Are the factors exact?
They follow SI and international definitions. Where a unit is approximate by nature (for example Mach, months or fuel economy), the page says so.
Can I convert in both directions?
Yes. Every pair page has a swap link and the calculator accepts any decimal value.