**The basic metric units for liquid volume are the liter and the milliliter.** Little difference exists between the metric liter and the quart, which is used to measure volume in the U.S. One quart is equivalent to 1.06 liters, and one liter equivalent to 0.95 quart, according to About.com.

The metric system requires much less complicated conversion methods because metric units are all in units of 10. In the system used in the United States, the conversions are much more involved and require memorization of equivalents. For instance, 1000 milliliters, 100 centiliters and 10 deciliters all equal one liter in the metric system. In the other system, however, two cups equal one pint, two pints equal one quart and four quarts equal one gallon. No continuity of conversion factors exists.