**Sixty-four fluid ounces is equivalent to 1.8927 liters.** Each liter is equal to 33.814 ounces, so 64/33.814 = 5.41. The easiest way to complete unit conversions is to use an online conversion calculator, which allows users to input numbers and choose units for conversion to receive an answer.

Although the liter is metric, it is not a unit in the International Systems of Units. Because the milliliter is equivalent to cubic centimeters, however, the mathematically related liter is widely accepted for use. Ounces are a standard measurement for liquid and weight in the United States. When converting from ounces to liters, assume the substance is a liquid.