Energy Converter

Exactly 4.184 for the thermochemical calorie, by definition. The food calorie is a kilocalorie, so exactly 4,184 joules.

To distinguish the kilocalorie from the small calorie used in physics — they differ by a factor of a thousand. Many labels now write kcal instead, which removes the ambiguity entirely.

Exactly 3.6 million. A kilowatt-hour is a kilowatt sustained for an hour, and an hour is 3,600 seconds.

Roughly the energy to raise a pound of water by one degree Fahrenheit. Several slightly different definitions exist; the international table BTU of 1,055.06 joules is the one usually meant.

One hundred thousand BTU, used for billing natural gas. It is about 105.5 megajoules or 29.3 kilowatt-hours.

About 4.2 kilojoules. A 2,000 kcal daily intake is about 8.4 megajoules, which is roughly 2.3 kilowatt-hours — less electricity than a tumble dryer uses in a single cycle.

It varies enormously by country, climate and house, so your own bill is the only reliable figure. What is consistent is that heating and hot water dominate in cold climates.

The energy gained by an electron crossing a one-volt potential — about 1.602 × 10⁻¹⁹ joules. It is the natural unit in particle physics, where joules are absurdly large.

By bomb calorimetry, or by the Atwater factors — 4 kcal per gram of protein and carbohydrate, 9 for fat, 7 for alcohol. Those factors are averages and they overstate energy from fibre.

Enthalpy includes the work done against constant pressure as well as internal energy. It is the more convenient quantity for reactions happening in an open beaker.

Roughly 32 to 34 megajoules, or about 9 kilowatt-hours. An engine converts a fraction of that to motion, which is why the tank is the size it is.

About the energy to lift a small apple one metre. It is a very small unit, which is why kilojoules and kilowatt-hours are used for anything domestic.