Dry measuring cups are meant to be filled right up to the top and then leveled off with a straight edge of some sort. Liquid measuring cups generally have a pour spout and are made to be filled to the gradations on the side of the cup (1/4 cup, 1/2 cup, 6 oz, etc.) rather than being filled right up to the top. read more
Test #2: Measuring Water in Both Dry and Liquid Measuring Cups. The same people then measured 1 cup of water (which should weigh 8.345 ounces) in both dry and liquid measuring cups. The dry cup varied by 23 percent, while the liquid cup varied by only 10 percent. read more
The volume measured by dry and liquid measuring cups typically used in the kitchen is the same. To be clear, I am using the word "cup" here to mean the container and not necessarily the unit of measure, so the same holds true for measuring a half cup, or quarter cup, using the appropriate sized measure. read more