Grams per cup to pounds per gallon (US) conversion calculator above calculates how many pounds per gallon (US) are in 'X' grams per cup (where 'X' is the number of grams per cup to convert to pounds per gallon (US)). In order to convert a value from grams per cup to pounds per gallon (US) (from g/cup to lb/gal) simply type the number of g/cup to be converted to lb/gal and then click on the 'convert' button.