Megajoules to kilowatt hours conversion calculator shown above calculates how many kilowatt hours are in 'X' megajoules (where 'X' is the number of megajoules to convert to kilowatt hours). In order to convert a value from megajoules to kilowatt hours (from MJ to kWh) just type the number of MJ to be converted to kWh and then click on the 'convert' button.