A measurement of 2/3 cup of butter is equal to 1 1/3 sticks of butter. One stick of butter is equal to 1/2 cup of butter.
Butter is made from cream, so occasionally cream works as a substitution for butter in recipes like scones or biscuits. Cream scones are a common Southern dish, though oil or margarine work best as substitutions in most recipes. When margarine is substituted for butter, an equal amount of margarine is used. However, when vegetable oil is substituted, a lesser amount of oil is needed. If the recipe calls for 1 cup of butter, 7/8 cup of vegetable oil is sufficient.