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