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Energy Converter

Convert between joules, calories, kilowatt-hours and more

Quick Conversions

Joule to Kilojoule Joule to Calorie Joule to Kilocalorie Joule to Watt-hour Joule to Kilowatt-hour Joule to BTU Joule to Electronvolt Kilojoule to Joule Kilojoule to Calorie Kilojoule to Kilocalorie Kilojoule to Watt-hour Kilojoule to Kilowatt-hour Kilojoule to BTU Kilojoule to Electronvolt Calorie to Joule Calorie to Kilojoule Calorie to Kilocalorie Calorie to Watt-hour Calorie to Kilowatt-hour Calorie to BTU Calorie to Electronvolt Kilocalorie to Joule Kilocalorie to Kilojoule Kilocalorie to Calorie Kilocalorie to Watt-hour Kilocalorie to Kilowatt-hour Kilocalorie to BTU Kilocalorie to Electronvolt Watt-hour to Joule Watt-hour to Kilojoule Watt-hour to Calorie Watt-hour to Kilocalorie Watt-hour to Kilowatt-hour Watt-hour to BTU Watt-hour to Electronvolt Kilowatt-hour to Joule Kilowatt-hour to Kilojoule Kilowatt-hour to Calorie Kilowatt-hour to Kilocalorie Kilowatt-hour to Watt-hour Kilowatt-hour to BTU Kilowatt-hour to Electronvolt BTU to Joule BTU to Kilojoule BTU to Calorie BTU to Kilocalorie BTU to Watt-hour BTU to Kilowatt-hour BTU to Electronvolt Electronvolt to Joule Electronvolt to Kilojoule Electronvolt to Calorie Electronvolt to Kilocalorie Electronvolt to Watt-hour Electronvolt to Kilowatt-hour Electronvolt to BTU

About Energy Conversion

Energy is the capacity to do work and exists in many forms including kinetic, potential, thermal, electrical, and chemical. The SI unit of energy is the joule (J), named after physicist James Prescott Joule. In everyday life, different energy units are used in different contexts: kilocalories (often simply called "Calories" on food labels) for nutrition, kilowatt-hours (kWh) for electricity billing, and BTU for heating and cooling systems.

The calorie (cal) is the energy needed to raise the temperature of one gram of water by one degree Celsius. The food Calorie (with a capital C) is actually a kilocalorie (kcal), equal to 1,000 small calories. This distinction often causes confusion but is important for accurate dietary calculations.

Kilowatt-hours are how electrical utilities measure energy consumption. One kWh equals 3.6 million joules and can power a 100-watt light bulb for 10 hours. At the atomic scale, the electronvolt (eV) measures the energy gained by an electron moving through a one-volt potential difference, a unit essential in particle physics and quantum mechanics.