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