For a standard main dish, the general rule of thumb is to allow about 80 to 100 grams (roughly 3 to 3.5 ounces) of dry spaghetti per adult. This will yield around 180 to 200 grams of cooked pasta once it absorbs water, which makes a satisfying, hearty plate.
If your guests have particularly large appetites or if the pasta is being served with a very light sauce (such as a simple aglio e olio), you might want to increase that slightly to around 110 to 120 grams (about 4 ounces) per person. On the other hand, if you are serving rich, meat-heavy sauces like bolognese or offering substantial appetizers, bread, and dessert, 75 to 80 grams per person is usually plenty.
To measure this accurately without a kitchen scale, a dry bunch of spaghetti measuring about the diameter of a standard bottle cap or a quarter coin represents roughly 2 ounces (around 60 grams). Therefore, a main course portion would be slightly thicker than that bundle. However, a digital scale is always the most dependable method to ensure consistent results.
