Energy Converter

Convert between different energy units with this easy-to-use converter.

Conversion Result

Common Energy Conversions

From To Conversion Factor
1 Joule (J) Calories (cal) 0.239006 cal
1 Kilowatt-hour (kWh) Joules (J) 3,600,000 J
1 British Thermal Unit (BTU) Joules (J) 1,055.06 J
1 Calorie (cal) Joules (J) 4.184 J
1 Electronvolt (eV) Joules (J) 1.60218 × 10⁻¹⁹ J

About Energy Units

SI Units

Joule (J): The SI unit of energy. One joule is equal to the energy transferred when a force of one newton acts over a distance of one meter.

Kilowatt-hour (kWh): A unit of energy commonly used for electricity billing. One kilowatt-hour equals 3.6 million joules.

Other Common Units

Calorie (cal): The amount of energy needed to raise the temperature of one gram of water by one degree Celsius.

Kilocalorie (kcal): Equal to 1000 calories. Often used in food energy content.

British Thermal Unit (BTU): The amount of energy needed to raise the temperature of one pound of water by one degree Fahrenheit.

Electronvolt (eV): The energy gained by an electron when it moves through an electric potential difference of one volt.

Erg (erg): A unit of energy in the CGS system. One erg equals 10⁻⁷ joules.

Foot-pound (ft⋅lb): The energy transferred when a force of one pound-force acts over a distance of one foot.

Therm (thm): A unit of energy used for natural gas billing. One therm equals 100,000 BTU.

Frequently Asked Questions

A kilocalorie (kcal) is equal to 1000 calories (cal). In nutrition, the term "calorie" is often used to mean "kilocalorie" - when you see "calories" on food labels, they actually refer to kilocalories. This is why a food item with 200 "calories" actually contains 200,000 calories or 200 kilocalories.

The kilowatt-hour is used because it's a practical unit for measuring electrical energy consumption. It represents the energy used by a 1000-watt appliance running for one hour. This makes it easy to understand and calculate electricity costs based on power consumption and usage time.

Power is the rate at which energy is used or transferred. Energy is power multiplied by time. For example, if a 100-watt light bulb is left on for 10 hours, it uses 1000 watt-hours (1 kilowatt-hour) of energy. The watt is the SI unit of power, while the joule is the SI unit of energy.