Pasta: every method

Pasta: cooked weight by method, from 100, 150 and 200 g raw
Method	Yield	100 g raw	150 g raw	200 g raw
Dry pasta, boiled	237.9%	238 g	357 g	476 g
Whole-wheat pasta, boiled	240.3%	240 g	360 g	481 g

Pasta: energy and protein per 100 g, raw and cooked, with sources
Method	Raw, per 100 g	Cooked, per 100 g	Source
Dry pasta, boiled	371 kcal · 13 g protein	158 kcal · 5.8 g protein	derived from dry matter · FDC 169736, FDC 169737
Whole-wheat pasta, boiled	352 kcal · 13.9 g protein	149 kcal · 6 g protein	derived from dry matter · FDC 169738, FDC 168910

Dry pasta cooks to about 237.9% of its weight: 100 g from the packet becomes about 238 g on the plate, and an 80 g portion becomes 190 g. Whole-wheat pasta is almost the same, at 240.3%.

What boiling does to pasta

Dry pasta is only 9.9 g of water per 100 g. Boiling fills it up to 62.1 g per 100 g in USDA's cooked entry, so the weight more than doubles while the rest of the pasta, the starch and protein, stays in the pot. Keeping that dry part constant gives the yield: (100 − 9.9) ÷ (100 − 62.13) = 2.38.

How long you boil it matters. Pasta cooked past al dente holds more water and weighs more; pasta drained early weighs less. USDA's entry doesn't say how long its samples were boiled, so treat 237.9% as a middle, not a rule.

A worked example

Boil 80 g of dry pasta and expect about 190 g once drained. The dry entry gives 297 kcal and 10 g of protein; the cooked entry, for 190 g, gives 301 kcal and 11 g. The energy stays where it was, because only water came in.

Should I weigh pasta dry or cooked?

Dry is easier: the packet is on the counter, the scale is at hand, and the dry entry doesn't depend on the yield. Cooked is fine too, as long as you use a cooked entry and weigh the pasta drained, before the sauce goes on. Pasta keeps taking up liquid while it sits in a sauce, which is why the drained weight is the one that matches the entry.

Does salt in the water change anything?

Not in USDA's data: its cooked pasta with added salt has the same 62.13 g of water per 100 g as the unsalted one, and 157 kcal against 158 kcal.

Sources

USDA FoodData Central, SR Legacy: enriched pasta dry, 169736 and cooked without salt, 169737; whole-wheat pasta dry, 169738 and cooked, 168910; enriched pasta cooked with salt, 169751.
The yields are derived from each pair's water content; the USDA Table of Cooking Yields for Meat and Poultry covers meat and poultry only.

For a whole pan of pasta with sauce, the recipe-portion calculator divides it by weight. See also rice, or the raw to cooked weight converter for other foods.