Energy Converter
Convert Joules, Kilojoules, Calories, Kilocalories, Watt-hours, Kilowatt-hours, BTU, Electronvolts, Therms, Foot-pounds & More
Free online energy converter for all common units. Instantly convert between joules, calories, kWh, BTU, electronvolts, therms, foot-pounds, and more.
What is an Energy Converter?
An energy converter is a tool that allows you to quickly and accurately convert between different units of energy, such as joules, calories, kilojoules, kilocalories, watt-hours, kilowatt-hours, BTU, electronvolts, therms, foot-pounds, and ergs. This is essential for science, engineering, nutrition, and everyday life when working with different measurement systems.
Supported Energy Units
- Joule (J): The SI unit of energy. Used worldwide in science and engineering.
- Kilojoule (kJ): 1,000 joules. Commonly used in food energy and science.
- Calorie (cal): 4.184 joules. Used in nutrition and chemistry.
- Kilocalorie (kcal): 1,000 calories. Also called "large calorie" or "food calorie".
- Watt-hour (Wh): 3,600 joules. Used for electrical energy.
- Kilowatt-hour (kWh): 1,000 watt-hours. Used for household electricity bills.
- BTU (British thermal unit): 1,055.06 joules. Used in heating and air conditioning.
- Electronvolt (eV): 1.60218×10⁻¹⁹ joules. Used in atomic and particle physics.
- Therm (US): 105,505,585 joules. Used for natural gas energy.
- Foot-pound (ft·lb): 1.35582 joules. Used in engineering and mechanics.
- Erg (erg): 1×10⁻⁷ joules. Used in physics, especially in the CGS system.
How to Use the Energy Converter
- Enter the value you want to convert.
- Select the unit you are converting from.
- View instant conversions to all other supported units below.
Why Use ManyCalcs Energy Converter?
- Completely free and ad-free.
- Supports all major energy units.
- Instant, accurate, and easy-to-use interface.
- Mobile-friendly and accessible on any device.
- Educational content for every unit.
Frequently Asked Questions
- How do I convert joules to calories?
- Enter the value in joules, select "Joule (J)", and view the result in calories in the output list.
- What is the difference between a calorie and a kilocalorie?
- 1 kilocalorie (kcal) = 1,000 calories (cal). Food calories are usually kilocalories.
- What is a BTU?
- BTU (British thermal unit) is used in heating and air conditioning. 1 BTU = 1,055.06 joules.
- Is this energy converter free?
- Yes, the ManyCalcs energy converter is 100% free and always will be.
For more information, see Units of energy on Wikipedia.