Energy Converter
Convert between energy units: Joules, Calories, kWh, BTU, Electron Volts.
About Energy Converter
Convert between energy units. 1 kcal = 4184 J = 4.184 kJ = 3.968 BTU.
How to Use Energy Converter
Enter a Value
Type the number you want to convert into the input field.
Choose Source Unit
Select the unit you are converting FROM using the dropdown menu.
Choose Target Unit
Select the unit you want to convert TO from the second dropdown.
Copy Your Result
The converted value appears instantly. All equivalent values are also shown below.
Key Features
High Precision
Uses scientifically accurate conversion factors for reliable results.
Real-Time Conversion
Values convert instantly as you type — no waiting.
Bidirectional
Easily swap between source and target units with one click.
All Units Shown
See conversions to all supported units simultaneously.
Works Offline
Once loaded, works without internet. All math is done locally.
Free Forever
No cost, no limits. Convert as many values as you need.
Common Use Cases
- Scientists and engineers converting between measurement systems
- Students completing homework and lab assignments
- Travelers converting units when visiting other countries
- Chefs and cooks converting recipe measurements
- Professionals needing quick, accurate unit conversions
Frequently Asked Questions
How accurate are the conversions?
Our converters use internationally recognized conversion factors. Results are calculated with JavaScript's full floating-point precision (up to 15 significant digits). Accuracy is comparable to scientific calculators.
Does this work without internet?
Yes! Once the page is loaded, all conversions work offline. All calculations are performed locally in your browser — no internet connection is needed for the math.
Can I convert from any unit to any other unit?
Yes, you can convert between any combination of supported units in both directions. The swap button (⇄) makes it easy to reverse the conversion direction.
Is there a limit on how many conversions I can do?
No limits at all. Convert as many values as you need, as many times as you want. It's completely free and unlimited.
Are the conversion factors up to date?
Our conversion factors are based on the latest internationally recognized standards (SI units, NIST). For currency, rates may vary — please check current exchange rates for financial decisions.