Solid measures must have unbroken smooth rims in order to make it possible to level off excess ingredients. POURfect makes beautifully accurate cups in a set of nine useful sizes: ⅛, ¼, ⅓, ½, ⅔, ¾, 1, 1½, 2 cup.
If not weighing flour, the most accurate way to measure it is to set the cup on a counter and to sift the flour into the cup, allowing it to mound above the rim. Then take a metal spatula or straightedge and sweep it across the rim, removing the excess flour. Never tap or shake the cup as that packs more flour into it, and the cake will be dry and heavy.