A stick of butter weighs 4 ounces, which is equivalent to 8 tablespoons. A stick of butter is also equivalent to 1/2 pound and 1/4 cup.
If a recipe calls for butter in ounces, simply divide the number of ounces by 4 to arrive at the required number of sticks. If a recipe calls for butter in tablespoons, divide the number of tablespoons by 8 to determine the number of sticks.
Conversely, if a recipe calls for butter in sticks, but no such butter is available, multiply the number of sticks by 4 to determine the amount necessary in ounces, or multiply it by 8 to determine the number of tablespoons.