Energy Converter
Common Energy Values
- 1 food Calorie (kcal) = 4,184 J = 3.968 BTU
- 1 kilowatt-hour = 3,600,000 J = 3,412 BTU
- 1 BTU = 1,055.06 J = 252 cal
- 1 eV = 1.602 × 10⁻¹⁹ J
- 1 foot-pound = 1.3558 J
Energy Unit Converter: Joules, Calories, kWh, BTU & More
Energy is measured in many different units depending on the context. Physicists use joules, nutritionists use kilocalories (food Calories), electricians use kilowatt-hours, and HVAC engineers use BTUs. This converter handles all common energy units so you can quickly translate between them for homework, engineering, or everyday calculations.
How to Use
- Enter a numeric value in the input field.
- Select the source unit from the dropdown.
- All equivalent values appear instantly below.
- The source unit card is highlighted in blue for reference.
FAQ
- What is the difference between a calorie and a kilocalorie?
- A calorie (cal) is the energy needed to raise 1 gram of water by 1 °C. A kilocalorie (kcal), also called a food Calorie (capital C), equals 1,000 calories. Nutrition labels typically use kilocalories.
- How many joules are in a kilowatt-hour?
- One kilowatt-hour equals exactly 3,600,000 joules (3.6 MJ). This is because 1 kWh = 1,000 watts × 3,600 seconds.
- What is a BTU?
- A British Thermal Unit (BTU) is the energy needed to raise 1 pound of water by 1 °F. It equals approximately 1,055 joules and is commonly used in heating and cooling systems.
- What is an electronvolt used for?
- An electronvolt (eV) is a tiny unit of energy used in particle physics and quantum mechanics. It equals the energy gained by a single electron accelerated through 1 volt of electric potential, approximately 1.602 × 10-19 joules.