How much dry pasta = how much cooked?
Dry pasta roughly doubles in weight when cooked (absorbing water equal to its own weight). The exact multiplier varies: long thin pasta (spaghetti) ≈ 2×, tubular pasta (penne) ≈ 2.25×, small shapes (macaroni) ≈ 2.5×, and couscous ≈ 3×. A standard serving is 75-100g dry (150-200g cooked). Use 1 liter of water per 100g of pasta — less water causes sticking and uneven cooking. Add 10g salt per liter (it should taste like seawater). Never add oil to the water — it prevents sauce from adhering. Start timing when water returns to a boil. For al dente, subtract 1-2 minutes from the package time. Reserve a cup of starchy pasta water before draining — it's the secret to emulsifying and thickening sauces.