Volume Measurements in the Metric System Metric Units of Volume Volume measures the capacity occupied by liquid, solid, or gas. Let's learn about the units for volume in the Metric System , or essentially, how much space something is taking up in three dimensions. We need to use liquid measuring cups and spoons for basic liquid measurements and conversions. Remember, there are weight measuring cups too, and make sure you use the correct one. The most significant units of volume in the Metric System of Measurements are, liter milliliter kiloliter We use these for liquid measurements every single day. Whether we're cooking, gardening, or filling a pool, we have to know the right unit to use. If you're trying to fill a swimming pool, you're probably going to want to use kiloliters more so than you would want to use milliliters. Remember, a milliliter is a small amount, and a kiloliter is quite large. When you're cooking, chances are you're probably going to use mil