Energy converter
Convert joules, kilowatt-hours, calories and BTU – from food energy to electricity consumption.
100 kcal=418.4 kJ
Conversion to all units
| joule (J) | 418,400 |
| kilojoule (kJ) | 418.4 |
| megajoule (MJ) | 0.4184 |
| watt-hour (Wh) | 116.22222 |
| kilowatt-hour (kWh) | 0.11622222 |
| calorie (cal) | 100,000 |
| BTU (BTU) | 396.56668 |
How energy conversion works
The converter calculates through the joule, the SI base unit of energy. The kilowatt-hour, in which electricity is billed, corresponds to 3.6 megajoules. The calorie is defined as 4.184 joules.
Beware of food calories: the energy content of food is given in kilocalories (kcal), even though they are colloquially called 'calories'. A daily intake of 2,000 kcal corresponds to 8,368 kJ, i.e. roughly 2.3 kWh.
Conversion examples
| Value | Result |
|---|---|
| 1 kWh | 3.6 MJ |
| 100 kcal | 418.4 kJ |
| 1 BTU | 1,055.06 J |
| 2,000 kcal | 2.32444 kWh |
| 1 MJ | 0.277778 kWh |
| 500 Wh | 1,800 kJ |
Frequently asked questions
How many joules are in a kilowatt-hour?
1 kWh = 3,600,000 J = 3.6 MJ. A watt-hour is 3,600 J – the energy of a 1 W device running for one hour.
What is the difference between a calorie and a kilocalorie?
1 kcal = 1,000 cal. Food energy values are always in kilocalories – when an apple is said to have '50 calories', that means 50 kcal, i.e. 209 kJ.
What is BTU?
British thermal unit – a unit used mainly for air conditioning and heating in English-speaking countries: 1 BTU = 1,055.06 J. Air conditioner output is given in BTU/h.
How do I convert kJ to kcal?
Divide the value by 4.184. A food with 1,000 kJ of energy has roughly 239 kcal.
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Last updated: 15 July 2026