3 cups. There are 4 sticks of butter to a pound, each stick measuring 1/2 c. 8 oz is half a pound, the equivalent of two sticks. So 1 1/2 lbs butter = 3 cups.

Because one tablespoon of butter is equivalent to 14.18 grams. There are 28.36 grams in two tablespoons of butter. This is also equivalent to one ounce of butter.