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Energy Converter

Your inputs

A food Calorie on a label is a kilocalorie. BTU here is the International Table BTU; specialist engineering uses slightly different BTU definitions.

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Convert joules and kilojoules to watt-hours, kilowatt-hours, calories, kilocalories and BTU — for electricity bills, food energy, heating and physics.

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UNDERSTAND YOUR RESULTS

Energy Converter guide

Convert joules and kilojoules to watt-hours, kilowatt-hours, calories, kilocalories and BTU — for electricity bills, food energy, heating and physics.

How to use this tool

  1. Enter the value you want to convert.
  2. Choose the source and destination units. Use Swap to reverse them.
  3. Compare the live equivalents, then copy a result or download the table as CSV.

A worked example

One kilowatt-hour of electricity is 3,600 kilojoules — about 860 kilocalories of food energy.

What you can do with this tool

How it works

Result = input × source-unit factor ÷ destination-unit factor. All factors are relative to the same base unit; intermediate values are not rounded.

Frequently asked questions

Which unit definitions are used?

Joules, Kilojoules, Watt-hours, Kilowatt-hours, Calories (thermochemical), Kilocalories, BTU, Foot-pounds. Read the labels carefully: regional or decimal/binary variants are separate choices.

Is a food Calorie the same as a calorie?

A label Calorie, with a capital C, is a kilocalorie: 1,000 small calories, or 4,184 joules. The converter lists calories and kilocalories as separate units.