Energy Converter
Enter an amount of energy in any unit to see it in every other unit at once.
How to use it
- Enter an amount Type the energy to convert.
- Choose the starting unit Select it in the "From" menu.
- Read the conversions All other units update instantly.
Examples
| 1 kWh | 3.6 MJ |
|---|---|
| 1 kcal | 4,184 J |
About this tool
Energy appears in many units across physics, nutrition and utilities. This converter links joules and kilojoules (the SI units), calories and kilocalories (used for food and heat), watt-hours and kilowatt-hours (electricity), and the BTU common in heating and air conditioning.
The factors use standard definitions, so conversions are precise. Everything runs in your browser.
Frequently asked questions
How many joules are in a kilowatt-hour?
Exactly 3,600,000 joules (3.6 megajoules). A kWh is the energy of one kilowatt used for one hour.
Is a food Calorie the same as a calorie?
A food "Calorie" (kcal) is 1,000 small calories. This tool labels them as kilocalories.
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Updated June 12, 2026