Convert energy measurements between joules, calories, watt-hours, kilowatt-hours and BTU.
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Result
0.001 kJ
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This tool converts between energy units using fixed conversion factors, for example, 1 kilowatt-hour equals 3,600,000 joules, 3,412 BTU, or roughly 860 kilocalories. Enter a value in any supported unit and it's converted to all others using these standard ratios.
Joules and kilojoules are the SI standard used in physics and on food labels in many countries. Calories and kilocalories (the 'Calories' on US food labels) measure food energy. Kilowatt-hours are used for electricity billing, and BTU is common for rating heating, cooling and appliance energy use in the US.
Converting 1 kilowatt-hour (a standard unit on an electricity bill) to joules gives exactly 3,600,000 J, and converting that same 1 kWh to kilocalories gives approximately 860.42 kcal, the same amount of energy your utility bills you for, expressed in food-energy terms.
Confusing a food 'Calorie' (capital C, actually a kilocalorie) with a scientific 'calorie' (lowercase, 1/1000th the size), reading a food label's Calories as if they were the smaller unit overstates actual energy by 1000x.
Mixing up energy (joules, calories, kWh) with power (watts, the rate energy is used), a kilowatt-hour is energy used over time, not an instantaneous rate, they're related but not interchangeable units.
Assuming BTU always means the same reference size, there are slightly different historical definitions of the BTU (thermochemical, international table, etc.), this tool uses the commonly cited international BTU (1,055.05585262 J), close enough for virtually all practical purposes.
Multiply kilowatt-hours by 3,600,000 to get joules, or use this converter for an instant result.
A food 'Calorie' (capital C) is actually a kilocalorie, equal to 1,000 small calories. This converter's 'calorie' and 'kilocalorie' units follow that same distinction.
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