Watt hours to terawatt hours converter on this page calculates how many terawatt hours are in 'X' watt hours (where 'X' is the number of watt hours to convert to terawatt hours). In order to convert a value from watt hours to terawatt hours (from Wh to TWh) type the number of Wh to be converted to TWh and then click on the 'convert' button.