Energy Converter
Convert work and thermodynamic energy values across physics, nutritional science, electrical utility billing, and mechanical engineering. Easily convert Joules, Kilowatt-hours, BTUs, Calories, and Foot-pounds.
Energy or thermodynamic work value to convert
Source energy measurement unit
Destination target energy unit
Energy magnitude in selected destination unit
How to Use This Calculator
- Enter the energy value you wish to convert.
- Select the starting unit (such as Joules, kWh, or Calories).
- Choose your target unit.
- View the converted result alongside SI Joules and electricity kWh equivalents.
Formula & Calculation Methodology
All thermodynamic and electrical energy converts through the SI base unit of Joules (J). 1 kWh is defined as exactly 3,600,000 Joules (1,000 W × 3,600 s). 1 thermochemical calorie is defined as exactly 4.184 Joules.
Worked Example
Converting 1,000 Joules to nutritional food calories (kcal)
Converting 1 kWh of household electrical power to BTU
Frequently Asked Questions
What is the difference between a small calorie (cal) and a food calorie (Cal / kcal)?↓
A dietary food calorie (often capitalized Calorie) is actually a kilocalorie (1 kcal = 1,000 gram calories = 4,184 Joules), representing the energy needed to heat 1 kilogram of water by 1°C.
How many Joules are in 1 kilowatt-hour (kWh)?↓
One kWh equals exactly 3.6 Megajoules (3,600,000 Joules), derived from 1,000 watts maintained over 3,600 seconds.
What is a BTU?↓
A British Thermal Unit (BTU) is the amount of heat energy required to raise the temperature of one pound of liquid water by 1°F at sea level, approximately equal to 1,055.06 Joules.
What is a limitation when comparing mechanical energy with thermal energy?↓
The Second Law of Thermodynamics dictates that while 100% of mechanical work can convert to heat, heat cannot be converted into mechanical work with 100% efficiency.
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Source Citation & Disclaimer
Informational tool only; not licensed tax, legal, or financial advice.