Watt hours to kilojoules conversion calculator shown above calculates how many kilojoules are in 'X' watt hours (where 'X' is the number of watt hours to convert to kilojoules). In order to convert a value from watt hours to kilojoules (from Wh to kJ) just type the number of Wh to be converted to kJ and then click on the 'convert' button.