Energy Unit Converter
Convert between joules, calories, BTU, watt-hours, kilowatt-hours, and more. Perfect for physics, nutrition, and energy calculations.
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All Conversions
Common Energy Conversions
| Description | Value | Equivalent |
|---|---|---|
| 1 food calorie | 1 kcal | 4,184 J = 4.184 kJ |
| 1 BTU | 1 BTU | 1,055 J = 252 cal |
| 1 kilowatt-hour | 1 kWh | 3.6 MJ = 3,412 BTU |
| Daily diet (2000 kcal) | 2,000 kcal | 8.37 MJ = 2.33 kWh |
| 1 therm (natural gas) | 100,000 BTU | 105.5 MJ = 29.3 kWh |
| 1 electron volt | 1 eV | 1.602 x 10^-19 J |
About Energy Units
Understanding Energy Units
Energy is the capacity to do work. Different fields use different units to measure energy, which is why conversions are so important. The SI unit of energy is the joule (J), but you will encounter many other units in daily life.
Common Energy Units Explained
- Joule (J): The SI unit of energy. One joule is the energy transferred when a force of one newton moves an object one meter.
- Calorie (cal): The energy needed to raise 1 gram of water by 1 degree Celsius. Used in chemistry and physics.
- Kilocalorie (kcal): Also known as the "food calorie" or "Calorie" (with capital C). This is what you see on nutrition labels. 1 kcal = 1000 cal.
- BTU (British Thermal Unit): Common in HVAC and heating. The energy needed to raise 1 pound of water by 1 degree Fahrenheit.
- Watt-hour (Wh) / Kilowatt-hour (kWh): Used for electrical energy. Your electricity bill is measured in kWh. 1 kWh = 1000 watts used for 1 hour.
- Electron Volt (eV): Used in particle physics and quantum mechanics. The energy gained by an electron moving through 1 volt of potential difference.
Practical Applications
- Nutrition: Food energy is measured in kilocalories (kcal). A typical adult needs about 2000 kcal per day.
- Electricity: Your home electricity usage is measured in kWh. A 100W light bulb running for 10 hours uses 1 kWh.
- Heating/Cooling: HVAC systems are often rated in BTU per hour (BTU/h), indicating their heating or cooling capacity.
- Physics/Chemistry: Scientific calculations typically use joules or kilojoules.