Megawatt hours to watt seconds conversion calculator above calculates how many watt seconds are in 'X' megawatt hours (where 'X' is the number of megawatt hours to convert to watt seconds). In order to convert a value from megawatt hours to watt seconds (from MWh to Ws) just type the number of MWh to be converted to Ws and then click on the 'convert' button.