Unit conversion
Energy Converter
Convert joules, kilojoules, watt-hours, kilowatt-hours, thermochemical calories, and IT British thermal units.
Convert a value
Your values are processed in your browser and are not uploaded to ToolPixels. This tool does not save them.
Energy and power are different quantities
Energy measures an amount of work or heat. A kilowatt-hour is energy, whereas a kilowatt is power. Convert power units with the Power Converter.
Calories here are thermochemical: 1 cal = 4.184 J and 1 kcal = 4,184 J. A dietary Calorie usually means a kilocalorie. Btu uses the International Table (IT) definition.
Example
1 kWh = 3.6 MJ.
Precision and input limits
Results use browser floating-point arithmetic and are rounded to your selected number of significant digits, not decimal places. Small or large results may use scientific notation. This is not an arbitrary-precision calculator.
Enter zero or a number with magnitude from 1e-100 to 1e100. Signed values are supported for mathematical conversions. Swap units exchanges the unit choices without changing your input. Editing an input clears the previous result.