Energy
Joules, calories and kilocalories, watt hours and kilowatt hours, BTU, kilogram-force metres and tonnes of oil equivalent.
Tool
Tools › Unit converters
How it is calculated
The value is converted to joules and from there to every unit. 1 kWh = 3.6 MJ, 1 kcal = 4.184 kJ (thermochemical), 1 BTU = 1055 J, 1 kgf·m = 9.80665 J (lifting 1 kg by 1 m).
Example: heating 1 L of water from 20 to 100 °C takes 80 kcal = 335 kJ = 0.093 kWh, not counting losses.
Keep in mind
- The “Calorie” on food labels is the kilocalorie. An adult needs about 2000-2500 kcal a day, about 2.3-2.9 kWh.
- There are small differences between the thermochemical calorie (4.184 J) and the international one (4.1868 J): they do not matter in practice.