Energy Converter

Convert between different energy units including joules, calories, kilowatt-hours, BTUs, electron volts, and more. Perfect for physics, engineering, chemistry, and everyday energy calculations.

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Common Conversions
Quick access to frequently used conversions
Unit Information

Metric Units

International System of Units (SI) measurements

J
metric
Joule
Base unit of energy in the SI system
kJ
metric
Kilojoule
1000 joules, common unit for food energy
MJ
metric
Megajoule
1 million joules, used for large energy values
GJ
metric
Gigajoule
1 billion joules, industrial energy unit

Imperial Units

Traditional British and American measurements

cal
imperial
Calorie
Energy needed to raise 1g of water by 1°C
kcal
imperial
Kilocalorie
1000 calories, food energy unit (Calorie)
BTU
imperial
British Thermal Unit
Energy to raise 1 lb of water by 1°F
therm
imperial
Therm
100,000 BTU, natural gas energy unit
ft-lbf
imperial
Foot-pound Force
Energy from 1 lb force over 1 ft distance
hp-hr
imperial
Horsepower-hour
Energy from 1 horsepower for 1 hour

Scientific Units

Scientific and technical measurements

Wh
scientific
Watt-hour
Energy from 1 watt for 1 hour
kWh
scientific
Kilowatt-hour
1000 watt-hours, electricity billing unit
MWh
scientific
Megawatt-hour
1 million watt-hours, power plant energy
eV
scientific
Electron Volt
Energy gained by electron in 1 volt potential
keV
scientific
Kiloelectron Volt
1000 electron volts, particle physics unit
MeV
scientific
Megaelectron Volt
1 million electron volts, nuclear physics
GeV
scientific
Gigaelectron Volt
1 billion electron volts, high-energy physics
erg
scientific
Erg
CGS unit of energy, 1 erg = 10⁻⁷ J
Preferences

Common Use Cases

  • Physics: Kinetic energy, potential energy, work calculations
  • Nutrition: Food energy, calorie counting, diet planning
  • Engineering: Power systems, HVAC, mechanical energy
  • Chemistry: Chemical reactions, bond energies, heat
  • Electricity: Power consumption, billing, efficiency

Popular Conversions

100 kcal418.4 kJ
1000 BTU0.293 kWh
1000 J239.0 cal
1 eV1.602e-19 J

How Our Energy Converter Works

1️⃣

Enter Energy Value

Input any energy value in the "From" field. Our converter accepts decimal numbers and scientific notation.

2️⃣

Select Units

Choose your source unit (e.g., kcal) and target unit (e.g., kJ) from our comprehensive unit selection.

3️⃣

Get Instant Result

View the converted energy value in real-time. Copy results, explore common conversions, or check conversion history.

Understanding Energy Units

SI Units (Metric)

J (Joule)
Base unit in the SI system. 1 J = 1 N⋅m = 1 kg⋅m²/s²
kJ (Kilojoule)
1000 joules, common unit for food energy and daily use.

Imperial Units

cal (Calorie)
Energy needed to raise 1g of water by 1°C.
BTU (British Thermal Unit)
Energy to raise 1 lb of water by 1°F, used in HVAC.

Scientific Units

eV (Electron Volt)
Energy gained by electron in 1 volt potential.
kWh (Kilowatt-hour)
1000 watt-hours, standard electricity billing unit.

Frequently Asked Questions

How accurate is this energy converter?

Our energy converter uses precise conversion factors and maintains accuracy up to 8 decimal places. All conversions are based on internationally recognized standards.

Can I convert negative energy values?

Yes, our converter supports negative values for applications like relative energy measurements, potential energy differences, or scientific calculations.

What is the highest energy value I can convert?

Our converter can handle energy values from -1 trillion to 1 quadrillion units, covering everything from subatomic particle energies to astrophysical energy scales.

How do I use scientific notation?

Enable "Show scientific notation" in preferences for very large or small values. You can also input values like 1e6 for 1,000,000.

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