Physicists measure energy in joules, because a joule is based entirely on metric units kg * m2 / s2. But a joule is a bit too small for the kinds of calculations we do on this wiki.
Here are some other energy units for comparison:
|watt second||1||Electrical power is often measured in watts. A watt is the same as 1 joule per second.|
|calorie (lowercase)||4||This is not the unit for measuring food. This is an old outdated unit.|
(show formal definition)|The amount of energy needed to heat 1 gram of water up by 1 degree Celsius.
|BTU||1,055||British Thermal Unit (used for heating, typically).|
|watt hour||3,600||Used in battery specs.|
|4,184||This is the unit used for measuring food energy.|
For example, "A diet of 2000 Calories" (which would be 8,368,000 joules).
(show formal definition of unit)|The amount of energy needed to heat 1 kilogram of water up by 1 degree Celsius.
|kilowatt hour||3,600,000||Used on electricity bills.|
|gallon gasoline||131,881,980||The amount of energy you'd get from burning 1 gallon of gasoline.|
|gigajoule||1,000,000,000||Enough energy to power a house for a week or two.|
|petajoule||1,000,000,000,000,000||Enough energy to power 32,000 homes for a year.|
|Mtoe||41,868,000,000,000,000||The energy in 1 million tons of crude oil.|
|quad||1,055,055,900,000,000,000||A quadrillion BTU (see unit defined above)|
|CMO||160,000,000,000,000,000,000||Cubic mile of oil. This is approximately how much energy the world uses in every 3 to 4 months.|
If you want to do more conversions or calculations, you can use the calculator.