One stick of butter is equal to 1/2 cup. If a full cup of butter is required for a recipe, two full sticks or 16 tablespoons of butter is needed.
Sticks of butter are easy to measure because measurement equivalents are generally marked on the wrapper with clear lines to cut the sticks to the exact measurement needed. If butter is bought by the pound, a cup of butter would be half the block, as a 1-pound block of butter contains 2 cups. When using butter for cooking, be sure to follow the recipe exactly for measurements and the ideal temperature of the butter.