Energy Converter - Joules, Calories, kWh, BTU
Free energy converter. Switch between joules, calories, kcal, watt hours, kWh and BTU instantly. Runs in your browser, private and offline.
Convert energy between joules, calories, kilocalories, watt hours, kilowatt hours and BTU. The result updates instantly in your browser.
How to Use Energy Converter - Joules, Calories, kWh, BTU
- Enter your value. Type the energy you want to convert in the Value box.
- Pick the From unit. Choose the unit your value is in, such as kilowatt hours.
- Pick the To unit. Choose the unit you want the answer in, such as joules. Use the swap button to flip them.
- Read the result. The converted value shows instantly, with the full formula below it.
- See every unit. The table lists your value in all energy units at once, and you can copy the result or a share link.
Frequently Asked Questions
How many joules are in a kilowatt hour?
There are 3,600,000 joules in one kilowatt hour, since a watt is one joule per second and an hour is 3600 seconds. The tool handles this for you.
What is the difference between a calorie and a kilocalorie?
One kilocalorie equals 1000 calories. The Calorie on food labels is actually a kilocalorie, which equals 4184 joules.
How do I convert joules to calories?
Divide the joules by 4.184, since one calorie equals 4.184 joules. For example, 100 joules is about 23.9 calories.
What is a BTU?
A British thermal unit is the energy needed to raise one pound of water by one degree Fahrenheit. It equals about 1055 joules and is common in heating and cooling.
Is my data sent anywhere?
No. The conversion runs entirely in your browser, so the values you enter never leave your computer and it works offline once loaded.
Can I see all energy units at once?
Yes. The table converts your value into every energy unit at the same time, from joules up to kilowatt hours.