Energy Converter Online Free
Convert energy units instantly. Switch between joules, kilojoules, calories, kilocalories, watt-hours, kilowatt-hours, BTU, electronvolts and more.
Convert Energy
1 cal = 4.184 J
1 kcal = 4,184 J
1 kWh = 3,600,000 J
Result
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How to Use the Energy Converter
Convert energy units in three simple steps.
1. Enter energy
Type the energy value you want to convert.
2. Choose units
Select the original energy unit and the target unit.
3. View result
See the converted value and common energy equivalents instantly.
Fast energy conversion for science, nutrition and electricity.
This Energy Converter helps students, engineers, electricians, fitness users and everyday users convert energy values across physics, food, heating and electricity units with browser-based calculations.
You can convert joules, kilojoules, calories, kilocalories, watt-hours, kilowatt-hours, megawatt-hours, BTU, therms, electronvolts, foot-pounds and more.
What is an energy converter?
An energy converter changes energy values from one unit to another, such as joules to calories, kilowatt-hours to joules or BTU to kilojoules.
It is useful for physics, electricity bills, nutrition, heating and cooling, engineering, fitness calculations, science homework and energy comparisons.
When should you use it?
- Converting kWh to joules
- Changing joules to calories
- Comparing kcal, kJ and food energy
- Working with BTU and watt-hours
- Studying science, electricity or engineering units
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Energy Converter FAQ
Common questions about converting energy units.
How many joules are in one kilowatt-hour?
One kilowatt-hour equals exactly 3,600,000 joules.
How many joules are in one calorie?
One small calorie equals 4.184 joules. One food Calorie equals 4,184 joules.
What is BTU?
BTU means British thermal unit. It is commonly used for heating, cooling and energy measurement.
Does this converter use a backend?
No. All energy conversions run directly in your browser with HTML, CSS and JavaScript.
Can I convert kWh to BTU?
Yes. Select kilowatt-hour as the original unit and BTU as the target unit to convert instantly.
What is the difference between calorie and kilocalorie?
One kilocalorie equals 1,000 small calories. Food Calories are usually kilocalories.
Can I copy the energy conversion result?
Yes. Click Copy Result to copy the current energy conversion.
Does it work on mobile?
Yes. This energy converter works on desktop, tablet and mobile browsers.