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