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