Who has not been guilty of cooking too much pasta? The tiniest shapes grow as soon as you turn your back. Most pastas increase to three times their size in cooking. Two ounces of pasta will mushroom into 1 ½ cups of cooked pasta, depending on the shape and size. In general, a pound of pasta serves four people as a main course, six as a first course. Also, what accompanies the pasta will affect the amount necessary. If, for example, sausage is part of the dish, less pasta is necessary than if peas are the only accompaniment.