Ounces per gallon (US) to grams per cup converter above calculates how many grams per cup are in 'X' ounces per gallon (US) (where 'X' is the number of ounces per gallon (US) to convert to grams per cup). In order to convert a value from ounces per gallon (US) to grams per cup (from oz/gal to g/cup) type the number of oz/gal to be converted to g/cup and then click on the 'convert' button.