Energy Converter

What Is Energy?

Energy is the capacity to do work or cause change. It is one of the fundamental quantities used in physics, engineering, chemistry, electricity, mechanics and many other scientific fields.

Energy can appear in many forms, including kinetic energy, potential energy, thermal energy, chemical energy, electrical energy, nuclear energy and radiant energy. Although these forms are different, they can be measured using compatible energy units.

The joule (J) is the SI unit of energy. Other commonly used units include kilojoules, megajoules, watt-hours, kilowatt-hours, calories, kilocalories, British thermal units (BTU), electronvolts and foot-pounds.

Energy Units Supported by This Converter

Joule Converter

The joule is the SI unit of energy and is widely used in physics, engineering and scientific calculations.

Common joule conversions include:

• 1 kJ = 1,000 J
• 1 MJ = 1,000,000 J
• 1 Wh = 3,600 J
• 1 kWh = 3,600,000 J
• 1 cal = 4.184 J

Kilowatt-Hour (kWh) Converter

A kilowatt-hour is a unit of energy commonly used for electricity consumption. Electricity meters and utility bills frequently report energy usage in kWh.

Therefore:

• 1 kWh = 3.6 MJ
• 1 MWh = 1,000 kWh
• 1 GWh = 1,000,000 kWh

For example, an electrical appliance rated at 1,000 watts operating continuously for 1 hour consumes approximately 1 kWh of energy.

Calories and Kilocalories

Calories are commonly associated with food and nutrition, while kilocalories are frequently used on food labels. In scientific calculations, the exact calorie definition matters.

A nutritional "Calorie" with a capital C is generally equivalent to one kilocalorie (kcal).

BTU Energy Converter

BTU, or British thermal unit, is commonly used for heating, air-conditioning, HVAC, fuel and thermal-energy calculations.

A useful electricity conversion is:

BTU should not be confused with BTU per hour (BTU/h). BTU measures energy, while BTU/h measures power or the rate of energy transfer.

Electronvolt (eV) Converter

The electronvolt is a very small unit of energy commonly used in atomic physics, particle physics, chemistry and quantum science.

Larger electronvolt units include:

• 1 keV = 1,000 eV
• 1 MeV = 1,000,000 eV
• 1 GeV = 1,000,000,000 eV

Foot-Pound Energy Converter

Foot-pound force (ft·lbf) is a traditional unit of mechanical work or energy used primarily in engineering and imperial measurement systems.

The foot-pound should be distinguished from pound-force units used for torque and from pound-mass. Context is important when interpreting imperial engineering measurements.

Energy Conversion Formulas

Electrical Energy

When power is measured in watts and time in seconds, the resulting energy is measured in joules.

Kinetic Energy

Where m is mass in kilograms and v is velocity in meters per second.

Potential Energy

Where m is mass, g is gravitational acceleration and h is height.

Thermal Energy

This equation can be used to estimate the heat required to change the temperature of a substance.

Common Energy Conversion Chart

Energy Conversion Examples

Convert 5 kWh to Joules

Therefore, 5 kWh = 18 MJ = 18,000,000 J.

Convert 10,000 J to kWh

Therefore, 10,000 joules is approximately 0.00278 kWh.

Convert 100 kcal to Joules

Therefore, 100 kcal = 418,400 J.

Convert 1 kWh to BTU

Therefore, 1 kWh ≈ 3,412.14 BTU.

Where Energy Conversion Is Used

Energy conversion is useful across many industries and everyday applications.

Electricity and Power Systems

Engineers use joules, watt-hours, kilowatt-hours and megawatt-hours to measure electrical energy, battery capacity, electricity usage and power-system consumption.

HVAC and Heating

BTU and related energy units are commonly used for heating and cooling calculations. Energy converters help compare thermal energy with SI units such as joules and megajoules.

Nutrition

Calories and kilocalories are widely used to describe the energy contained in food.

Engineering

Mechanical engineers may encounter joules, foot-pounds, kilojoules and other units when calculating mechanical work and energy.

Physics and Science

Joules and electronvolts are important units in physics. Electronvolts are particularly useful for atomic, nuclear and particle-energy calculations.

Energy and Utilities

Electricity consumption is usually measured in kWh, while large-scale energy production may be expressed in MWh, GWh or other large units.

Energy vs Power

Energy and power are related but they are not the same quantity.

For example, a 2 kW appliance running for 3 hours consumes:

For power calculations, use our Power Converter.

How to Use the Energy Converter

1. Enter the energy value you want to convert.
2. Select the original energy unit.
3. Select the unit you want to convert to.
4. Click Convert.
5. Use Copy Result to copy the converted value.
6. Use Swap Units to reverse the conversion.

The calculator also updates automatically when the value or selected units are changed.

Energy Conversion Accuracy

Smart Unit Calc uses defined conversion factors where applicable and displays results with appropriate numerical precision. Very small values, such as electronvolts converted to joules, may require scientific notation.

Frequently Asked Questions About Energy Conversion

Related Unit Converters

Popular Energy Conversion Searches

This Energy Converter is designed for common searches such as joules to kWh, kWh to joules, joules to calories, calories to joules, kcal to joules, joules to BTU, BTU to joules, kWh to BTU, BTU to kWh, watt-hours to kWh, megajoules to joules, joules to electronvolts, electronvolts to joules and foot-pounds to joules.

It is also useful for electricity, HVAC, engineering, physics, chemistry, nutrition, mechanical work, thermal energy and scientific calculations.