Energy Converter
Convert between joules, calories, kilowatt-hours, BTU, and more.
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Energy conversion connects nutrition, electricity, thermodynamics, and physics. Joules (SI), calories (nutrition), kWh (electricity), BTU (HVAC), and eV (physics).
Calories vs Kilojoules
1 kcal (Calorie) = 4.184 kJ. Australia uses kJ on labels; US uses Calories. 2,000 Cal diet = 8,368 kJ.
Electricity: kWh and Joules
1 kWh = 3,600,000 J. Australian household uses 15–20 kWh/day (~54–72 MJ).
How to Use This Calculator
- Select 'Energy'
Choose the category from the dropdown.
- Select your source unit
Pick the unit you're converting from.
- Enter the value
Type the number. Results update instantly.
- Select your target unit
Choose the unit you need.
Applications
Nutrition and Dietetics
500 Calories = 2,092 kJ. Understanding both helps read international nutrition labels.
Electricity and Solar
5 kW solar system produces ~20 kWh/day. Convert to compare across energy sources.
HVAC
12,000 BTU/hr air conditioner ≈ 3.5 kW. Common for room-size units.
Energy Efficiency in Buildings
Our energy converter tool can help architects and building managers design more efficient buildings by comparing the energy consumption of different materials, such as insulation, windows, and HVAC systems. For example, they can use our tool to compare the energy efficiency of different types of roofing materials or to determine the most cost-effective heating and cooling systems for a particular building.
Frequently Asked Questions
How do you convert Calories to kJ?
Multiply by 4.184. 500 Cal = 2,092 kJ. Food 'Calories' are kilocalories.
How do you convert kWh to joules?
1 kWh = 3,600,000 J = 3.6 MJ.
What is a BTU?
British Thermal Unit: energy to heat 1 lb water by 1°F. 1 BTU = 1,055 J.
How do you convert energy from one form to another?
Our energy converter tool allows you to convert different forms of energy, such as electricity, gas, and solar power, into a common unit for easy comparison.
Can you help me understand the difference between kilowatt-hours and megajoules?
Sure! Kilowatt-hours (kWh) are a measure of energy consumption, while megajoules (MJ) are a measure of energy content. Think of it like this: kWh is how much energy you use in an hour, while MJ is the amount of energy you have available to use.