Energy Converters
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📦
SI / Metric
joules
kilojoules
megajoules
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Heat & Food
calories
kilocalories
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Electrical
watt-hours
kilowatt-hours
megawatt-hours
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Imperial
BTU
foot-pounds
⚗️
Scientific
electronvolts
ergs
About energy conversions
Energy conversions are essential in physics, engineering, nutrition, and everyday life. The SI unit is the joule, but kilowatt-hours (kWh) are used for electricity billing, calories and kilocalories for food energy, and BTU for heating and cooling systems.
One kilowatt-hour equals 3,600,000 joules. One food calorie (kilocalorie) equals 4,184 joules. One BTU equals approximately 1,055 joules. These conversions are not covered by Google's built-in converter, making them high-value search targets.
For the international definition, see the NIST reference on SI units of energy.
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