Spaghetti Sizes, Numbers & Weight Conversions

Numbers printed beside spaghetti names are not a universal inch or millimeter scale. They identify a product in a brand’s range. For example, Barilla lists Spaghetti N°5, while De Cecco lists Spaghetti n°12. Both names identify spaghetti products, so the numbers should not be compared across brands as if No. 12 were a standard thickness or length. Check the exact package or manufacturer’s product details for a specific variety. Barilla Spaghetti N°5 · De Cecco Spaghetti n°12.

If you need a particular noodle thickness or strand length, compare the exact product specifications or measure a dry strand. Names such as “spaghetti” and numbers on the box do not guarantee identical dimensions from every manufacturer. Also keep pasta shape in mind: spaghetti is round, while other long pasta cuts may be flat or hollow, so their width or diameter is measured differently.

1 pound of dry spaghetti equals about 454 grams (453.59237 g exactly under the U.S. customary pound definition). This is the dry package weight; cooking adds water, so cooked pasta weighs more. NIST conversion factors.