It supports joules (J), kilojoules (kJ), calories (cal), kilocalories (kcal), watt-hours (Wh), kilowatt-hours (kWh), and BTU.
A kilocalorie (kcal) equals 1000 calories. The calories listed on food labels are actually kilocalories.
One kilowatt-hour equals 3,600,000 joules (3.6 MJ). This is the unit used on electricity bills.
One calorie (small calorie) equals 4.184 joules. One kilocalorie (food calorie) equals 4,184 joules.
One litre of petrol contains approximately 34.2 MJ (megajoules) or about 9.5 kWh of energy.
A typical UK household uses about 8-10 kWh per day. A US household uses about 30 kWh per day.
Energy is the total amount of work done (measured in joules or kWh). Power is the rate at which energy is used (measured in watts). Power × Time = Energy.