What does one stick of butter equal in cups?
U.S. butter is typically sold in packages of 1/2-pound or 1-pound sticks, although you can get tubs of butter meant more for spreading on bread than for baking. The butter sticks are individually wrapped and weigh about 1/4 pound, or 1/2 cup. The wrapping over the butter includes various measurement breakdowns so it is easier to take the exact amount needed for the recipe. Source: nigella.com