There are 3 1/3 cups of all-purpose flour in a pound. Different kinds of flour are more or less refined and have different densities. Flours with higher densities weigh more than those with lower densities, and weight also depends on whether the flour is sifted or packed.
Cups are volume measurements and are better-suited to measure liquids. One cup equals 8 U.S. fluid ounces. Cups are often used in culinary recipes to measure ingredients as well. If a recipe uses pounds to measure flour, a kitchen scale can be a helpful and cost-effective way to make sure ingredient proportions are right.