Energy Converter

Convert between joules, calories, kilowatt-hours, BTU, and more.

1 J = 0.001 kJ
UnitValue
Kilojoule (kJ)0.001
Calorie (cal)0.2390057361
Kilocalorie (kcal)0.0002390057361
Watt-hour (Wh)0.0002777777778
Kilowatt-hour (kWh)2.777778e-7
BTU0.0009478133945

How many joules in a calorie?

1 calorie = 4.184 joules. 1 kilocalorie (food calorie) = 4,184 joules.

How many joules in a kWh?

1 kWh = 3,600,000 joules (3.6 MJ).

How many joules in a BTU?

1 BTU = 1055.06 joules.

What is the difference between cal and kcal?

In nutrition, "Calorie" (capital C) = kilocalorie = 1000 cal. 1 food Calorie = 4184 J.

How to Use Energy Converter?

  1. 1Enter your input values, numbers, or dates into the fields above.
  2. 2Adjust calculation parameters, units, or values to fit your specific needs.
  3. 3View the calculated result instantly. Many of our tools provide complete breakdowns, tables, or interactive details below.

Easy & Instant

Get results in real-time as you type or adjust your inputs for Energy Converter.

High Accuracy

All mathematical calculations use industry-standard formulas to guarantee accurate outputs.

Free & Secure

Calculate with complete privacy. Your inputs are never sent to our servers — everything is computed locally.

Frequently Asked Questions

Is Energy Converter free to use?
Yes, Energy Converter is 100% free with no hidden charges, premium subscriptions, or limits. You can use it as much as you need.
How does the Energy Converter tool work?
Convert between joules, calories, kilowatt-hours, BTU, and more. All operations are processed entirely inside your web browser using HTML5 features. Your files or input data are never uploaded to any server.
Is my data secure with Energy Converter?
Absolutely. Since the processing runs client-side in your own browser, your data never leaves your device. This makes it completely secure and private.