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Energy Converter

EducationMathProductivityScience

Convert between joules, calories, kilowatt-hours and more with our free Energy Converter. Instant, accurate energy unit conversions for science and everyday use.

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IN/OUT

Auto Process Client Side

Bulk Mode

Two-Unit
All Units

Formula

Change any value and the other will be calculated automatically

Joule (J)

Kilojoule (kJ)

Megajoule (MJ)

Gigajoule (GJ)

Calorie (cal)

Kilocalorie (kcal)

Watt Hour (Wh)

Kilowatt Hour (kWh)

Megawatt Hour (MWh)

Gigawatt Hour (GWh)

British Thermal Unit (BTU)

Therm (thm)

Foot-Pound (ft⋅lb)

Electronvolt (eV)

Kiloelectronvolt (keV)

Megaelectronvolt (MeV)

Gigaelectronvolt (GeV)

Erg (erg)

Tonne of Oil Equivalent (toe)

Tonne of Coal Equivalent (tce)

Barrel of Oil Equivalent (boe)

Quad (quad)

Thermie (th)

Horsepower Hour (hp⋅h)

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Guide

About Energy Converter

Our Energy Converter is a digital tool that transforms energy measurements from one unit to another. This online utility helps users quickly convert between various energy units such as joules, calories, kilowatt-hours, and more without manual calculations.

Key Features

Two-Unit Conversion: Convert directly between any two energy units
All Units Conversion: See a single value converted to multiple units simultaneously
Formula Display: View the exact conversion formula being used
Bulk Mode: Convert multiple values at once
Client-Side Processing: All calculations happen in your browser for privacy and speed

Supported Energy Units

Scientific Units	Electrical Units	Thermal Units	Other Units
Joule (J)	Watt Hour (Wh)	Calorie (cal)	Foot-Pound (ft⋅lb)
Kilojoule (kJ)	Kilowatt Hour (kWh)	Kilocalorie (kcal)	Erg (erg)
Megajoule (MJ)	Megawatt Hour (MWh)	British Thermal Unit (BTU)	Electronvolt (eV)
Gigajoule (GJ)	Gigawatt Hour (GWh)	Therm (thm)	Horsepower Hour (hp⋅h)

How to Use

Select “Two-Unit Conversion” or “All Units Conversion” mode
Enter the value you want to convert in the left input field
Select the source unit from the dropdown menu
Select the target unit from the second dropdown menu (for Two-Unit mode)
View the conversion result instantly
Toggle “Bulk Mode” if you need to convert multiple values

When to Use an Energy Converter

Physics and Engineering: Convert between scientific energy units for calculations
Electrical Engineering: Transform between watt-hours and joules for power systems
Nutrition and Dietetics: Convert between calories and kilojoules for food energy content
Utilities and Billing: Understand energy consumption in different units
Environmental Science: Compare energy sources using standardized measurements

Benefits of Using This Energy Converter

Accuracy: Precise conversions based on standard scientific formulas
Comprehensive: Support for specialized units like toe (tonne of oil equivalent) and boe (barrel of oil equivalent)
Time-Saving: Instant results without manual calculations
Educational: View the actual conversion formulas to understand the relationships between units
No Installation Required: Works on any device with a web browser

For more information on energy measurement systems, visit the U.S. Energy Information Administration or the International Energy Agency.

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 FAQ

What's the difference between a calorie and a kilocalorie?

A calorie (cal) is the energy needed to raise the temperature of 1 gram of water by 1°C. A kilocalorie (kcal) is 1,000 calories and is the unit commonly referred to as "Calories" (with a capital C) in food nutrition labels. 1 kcal = 4,184 joules.
How do I convert joules to kilowatt-hours?

To convert joules to kilowatt-hours, divide the joule value by 3,600,000. For example, 3,600,000 joules = 1 kWh. Our converter performs this calculation automatically when you select these units.
What energy unit is used on my electricity bill?

Most residential electricity bills use kilowatt-hours (kWh) as the standard unit of energy consumption. Some countries may use megajoules (MJ) instead, but kWh is the most common global standard for utility billing.
How do I convert food calories to joules?

Food calories are actually kilocalories (kcal). To convert food calories to joules, multiply by 4,184. For example, a 250 Calorie food item contains 1,046,000 joules of energy. The converter handles this calculation automatically.
How accurate is this energy converter?

This energy converter uses precise scientific conversion factors and mathematical formulas to provide highly accurate results. The conversions are based on internationally recognized standards and are suitable for both everyday use and scientific applications