Energy Converter

Convert between different energy units including joules, kilowatt-hours, BTU, calories, electron-volts and more.

All conversions happen locally in your browser. No data is sent to servers or stored remotely.
Precision: 4Format: Decimal
Round (decimal places):
Number format:
2.7778e-7

1 J = 2.7778e-7 kWh

Quick Conversions

💡Tips

1 kWh = 3.6 million joules (3.6 MJ)

Food calories (kcal) = thermochemical calories × 1000

BTU commonly used for heating/cooling capacity

Use the swap button to quickly reverse conversion

📊Conversion Table

Convert 1 J to:

Metric System

Kilowatt Hour (kWh)
2.7778e-7
Kilojoule (kJ)
0.001
Kilocalorie (food) (kcal)
0.0002
Watt Hour (Wh)
0.0003
Calorie (small) (cal)
0.239
Megajoule (MJ)
1.0000e-6
Megawatt Hour (MWh)
2.7778e-10
Gigajoule (GJ)
1.0000e-9

Imperial System

British Thermal Unit (BTU)
0.0009
Therm (US) (thm)
9.4782e-9
Foot-Pound (ft⋅lbf)
0.7376
Quad (quad)
9.4782e-19

Scientific

Electron Volt (eV)
6.2415e+18
Kiloelectron Volt (keV)
6.2415e+15
Megaelectron Volt (MeV)
6.2415e+12
Hartree Energy (Eh)
2.2937e+17
Rydberg (Ry)
4.5874e+17
METRIC SYSTEM(8 units)
Kilowatt Hour (kWh)
2.7778e-7
Kilojoule (kJ)
0.001
Kilocalorie (food) (kcal)
0.0002
Watt Hour (Wh)
0.0003
Calorie (small) (cal)
0.239
Megajoule (MJ)
1.0000e-6
Megawatt Hour (MWh)
2.7778e-10
Gigajoule (GJ)
1.0000e-9
IMPERIAL SYSTEM(4 units)
British Thermal Unit (BTU)
0.0009
Therm (US) (thm)
9.4782e-9
Foot-Pound (ft⋅lbf)
0.7376
Quad (quad)
9.4782e-19
SCIENTIFIC(5 units)
Electron Volt (eV)
6.2415e+18
Kiloelectron Volt (keV)
6.2415e+15
Megaelectron Volt (MeV)
6.2415e+12
Hartree Energy (Eh)
2.2937e+17
Rydberg (Ry)
4.5874e+17

What is an Energy Converter?

The Energy Converter is a powerful online tool for converting between different units of energy. Whether you're working in physics, engineering, electrical systems, or nutrition, this tool provides accurate conversions between joules, kilowatt-hours, BTU, calories, and many more energy units.

Our converter supports 23+ energy units including SI units (joules, kilojoules, megajoules), electrical units (watt-hours, kilowatt-hours), thermal units (BTU, therms), food energy (calories, kilocalories), and scientific units (electron-volts). Perfect for engineers, scientists, students, and anyone working with energy measurements.

Key Features:

  • Comprehensive Units: 23+ energy units including J, kJ, MJ, kWh, BTU, cal, kcal, eV
  • Multiple Systems: SI, imperial/US, food energy, particle physics units
  • Instant Results: Real-time conversion as you type
  • High Precision: Adjustable decimal precision up to 4+ places
  • Quick Conversions: One-click buttons for common scenarios
  • Privacy Friendly: All calculations performed in your browser

Perfect For: Physicists, engineers, electricians, nutritionists, students, and anyone needing accurate energy unit conversions.

Frequently Asked Questions

What's the difference between joules and calories?

A joule (J) is the SI unit of energy, while a calorie (cal) is a traditional unit. 1 calorie = 4.184 joules. In nutrition, "Calories" (with capital C) are actually kilocalories (kcal): 1 Cal = 1,000 cal = 4,184 J.

How do I convert kWh to joules?

One kilowatt-hour (kWh) equals 3,600,000 joules or 3.6 megajoules (MJ). The formula is: kWh × 3,600,000 = joules. For example, 1 kWh = 3.6 MJ. This is commonly used for electricity billing.

What is a BTU and when is it used?

BTU (British Thermal Unit) is the energy needed to raise 1 pound of water by 1°F. 1 BTU = 1,055 joules. It's commonly used in the US for heating, cooling, and air conditioning system ratings (e.g., "12,000 BTU air conditioner").

How many calories are in a kilowatt-hour?

One kilowatt-hour equals 860,421 calories (cal) or 860.421 kilocalories (kcal/Cal). This conversion is sometimes used to compare electrical energy to food energy or metabolic output.

What is an electron-volt (eV)?

An electron-volt is a tiny unit of energy used in particle physics: 1 eV = 1.602 × 10⁻¹⁹ joules. It's the energy gained by an electron moving through 1 volt of electric potential. Common in atomic and nuclear physics.