To convert a volume measurement in ounces to milliliters, simply multiply it by... There are approximately 29.574 milliliters (mL) per US liquid ounce (fl. oz). To convert a volume measurement in ounces to milliliters, simply multiply it by... There are approximately 29.574 milliliters (mL) per US liquid ounce (fl. oz). To convert a volume measurement in ounces to milliliters, simply multiply it by 29.574. Continue Reading