Energy Converter

Convert energy between joules and other supported energy units. Enter your own values below to see converted value and check the method behind it.

All calculators

Your inputs

Change the example values to match your situation.

Your result

Let’s work it out.

Fill in your inputs and select Calculate.
Your result and breakdown will appear here.

How this calculator works

Converted value = input × source unit factor ÷ destination unit factor.

Before you use the result

  • Calories use the thermochemical definition. BTU uses the international table definition.

KEEP EXPLORING

View category
Length ConverterArea ConverterVolume ConverterWeight ConverterTemperature ConverterSpeed Converter

What is Energy Converter?

Energy Converter helps you convert energy between joules and other supported energy units.

The main result is converted value, with a breakdown of conversion factor. The formula, example and assumptions below explain how to interpret it.

How to use Energy Converter

Use the example to get familiar with the form, then enter your own figures. Any rates in the example are illustrative. Check the field labels and units before calculating.

  1. Gather value, from unit and to unit. Use values from the same situation or reporting period.
  2. Replace the example value with your own value, then complete the other fields. Check the displayed units and each selected option.
  3. Select Calculate and read converted value with its result breakdown. Change one input and calculate again to compare a second scenario. Reset restores the original example.
  • Enter value, at least 0. Decimals are accepted.
  • Choose from unit from joules, kilojoules, watt hours, kilowatt hours, calories, kilocalories and BTU.
  • Choose to unit from joules, kilojoules, watt hours, kilowatt hours, calories, kilocalories and BTU.

Energy Converter: a worked example

With the inputs below, the result is 0.001 kilojoules (converted value). Follow the example, then replace these illustrative values with your own.

Example inputs and output
Input or outputExample value
Value1
From unitjoules
To unitkilojoules
Converted value0.001 kilojoules
Conversion factor0.001

Understanding the Energy result

Read converted value alongside conversion factor. These describe different parts of the same calculation.

Displayed results use a readable number of decimal places. When checking a result by hand, keep extra precision until the last step. To compare scenarios, change one input at a time and keep the others fixed.

  • Example Conversion factor: 0.001

Energy Converter: assumptions and common mistakes

A useful estimate starts with the right inputs. Check the following assumptions and limits before applying the result to your situation.

  • Calories use the thermochemical definition. BTU uses the international table definition.
  • Select the correct unit system. US and imperial gallons differ, local land units vary, and exchange rates need a dated source.

For wider guidance, visit NIST measurement units. The formula and scope of this specific tool are stated on this page.

Energy Converter FAQs

What does Energy Converter calculate?

Energy Converter helps you convert energy between joules and other supported energy units. Its main output is converted value in kilojoules.

What inputs do I need for Energy Converter?

You need value, from unit and to unit. Use the field labels and units to match your figures to the formula.

Which formula does Energy Converter use?

Converted value = input × source unit factor ÷ destination unit factor.

What is a worked example for Energy Converter?

Example inputs: Value: 1; From unit: joules; To unit: kilojoules. The result is 0.001 kilojoules (converted value).

How should I enter value?

Enter value, at least 0. Decimals are accepted.

How do I choose from unit?

Choose from unit from joules, kilojoules, watt hours, kilowatt hours, calories, kilocalories and BTU. The example uses joules; replace it if your circumstances differ.

How should I read converted value?

Read converted value alongside conversion factor. These describe different parts of the same calculation.

Why might my Energy Converter result differ from my records?

Calories use the thermochemical definition. BTU uses the international table definition. Differences in entered values, units or rounding can also change the comparison.

Can I compare two scenarios in Energy Converter?

Yes. Note your first converted value, change value or another input, and select Calculate again. Editing a field clears the old result so it is not mistaken for a new calculation.

Is Energy Converter free, and where are my inputs calculated?

This calculator is free to use without signing in. Its formula runs in your browser; calculator inputs are not sent to a calculation API. The inputs reset to the example values when you reset the form or start a fresh page.