Hello, if you need to quickly and correctly convert fluid ounces (US) to milliliters, use the online volume unit calculator. Using the converter is very easy - just specify the number to be converted from American fluid ounces to milliliters and click the "Calculate" button. After this simple step, you will find out how many milliliters are in your specified US fluid ounces. In the same way, you can calculate how many ounces in a gallon. In fact, this is all quite simple.