Dry to Cooked Pasta Calculator

Background.

A hundred grams of dry spaghetti comes out of the pot at about 237 g. The extra weight is water: dry pasta is roughly 10% water and cooked pasta roughly 62%, so every strand takes on more than its own weight from the pot. That ratio matters whenever a recipe, a meal plan or a calorie tracker gives pasta in one state and you have it in the other. A recipe asking for 500 g of cooked penne needs only about 192 g from the box.

The yields come from the USDA Food Buying Guide for Child Nutrition Programs, the table US school kitchens use to buy and portion food. For each of eight enriched white-semolina shapes it records how many pounds of cooked pasta one pound of dry produced and how long it was boiled. Spaghetti, measured al dente at 8 minutes, is the lowest at 2.37 times; orzo and ramen are the highest at 3.07. A second, separate USDA dataset backs the spaghetti figure: the water contents in FoodData Central predict a yield of 2.379, within 0.4% of the measured one.

Weight is the dependable answer. The guide's cup figures are food-service portions, and they hold much more pasta than a loosely filled kitchen cup — about 203 g of cooked spaghetti per USDA cup against 124 g in a household cup, by FoodData Central's measure. Shapes the guide gives only in cups, including elbow macaroni, rotini and whole-wheat varieties, are left out rather than given a weight yield nobody measured, and gluten-free pastas are not in the table at all.

What is dry to cooked pasta calculator?

The yield factor is cooked weight divided by dry weight. Boiling adds water and removes almost nothing else, so the factor is set by how much water the pasta absorbs, which depends on the shape, the flour and especially the time in the pot. The figures here are USDA's measurements for enriched semolina pasta at stated boil times: spaghetti 2.37 at 8 minutes, penne 2.60 at 14, medium shells 2.53 at 12, large bowties 2.66 at 17, medium wagon wheels 2.79 at 12, orzo 3.07 at 14, lasagna noodles 2.66 at 15 and ramen 3.07 at 3.

How to use this calculator.

1. 01Choose the direction: dry → cooked if you are weighing pasta from the packet, cooked → dry if a recipe or meal plan gives a cooked weight.
2. 02Pick the shape. The boil time USDA used is shown with it, so you can tell whether your own cooking runs longer or shorter.
3. 03Enter the weight and choose grams, ounces or pounds. Weigh rather than measuring by the cup; a cup of dry shells and a cup of dry elbows differ by almost half.
4. 04Read the cooked and dry weights first, then the serving counts if you are cooking for a group.

The formula.

Dry to cooked: W_cooked = W_dry × Y, where Y is the shape's USDA yield. Cooked to dry: W_dry = W_cooked ÷ Y. Every other output is then built from the dry weight, so converting one way and back returns the starting figure. Units convert at exactly 28.349523125 g per ounce and 453.59237 g per pound.

Volume uses the guide's second column, the number of ¼-cup cooked servings one pound of dry pasta gives (S¼). USDA cups = dry pounds × S¼ × 0.25, and ½-cup servings are half the ¼-cup count. Consumer servings divide the dry weight by 2 oz, the serving declared on US pasta packets.

The spaghetti yield can be checked by conservation of dry matter. FoodData Central lists dry enriched pasta at 9.90 g of water per 100 g, leaving 90.10 g of solids, and cooked pasta at 62.13 g of water, leaving 37.87 g of solids per 100 g. Those solids must be the same before and after, so 100 g dry becomes 90.10 ÷ 0.3787 = 237.9 g cooked, a factor of 2.3792.

The factors apply to drained pasta cooked for about the stated time. Boiling longer lets pasta keep absorbing water, so an overcooked batch weighs more than predicted.

A worked example.

Frequently asked questions.

References& sources.

1. [1]U.S. Department of Agriculture, Food and Nutrition Service. "Food Buying Guide for Child Nutrition Programs," Section 4 (Grains) yield table, heading PASTA (Group H) — per-shape rows giving cooked pounds per pound dry, boil time, and ¼-cup servings per pound. Retrieved 2026-07-30; the yield-table PDF carries no printed revision date.
2. [2]U.S. Department of Agriculture, Agricultural Research Service. FoodData Central, SR Legacy record 169736, "Pasta, dry, enriched" (published 2019-04-01) — water 9.90 g/100 g; dry cup weights by shape (spaghetti 91 g, elbows 122 g, penne 95 g, farfalle 81 g, rotini 96 g, shells 64 g, lasagna 90 g); 2 oz = 57 g.
3. [3]U.S. Department of Agriculture, Agricultural Research Service. FoodData Central, SR Legacy record 169737, "Pasta, cooked, enriched, without added salt" (published 2019-04-01) — water 62.13 g/100 g, 158 kcal/100 g; household portions including 1 cup spaghetti not packed = 124 g, packed = 151 g.
4. [4]National Institute of Standards and Technology. NIST Special Publication 811 (2008 edition), Table B.8 — avoirdupois ounce = 28.349523125 g and pound = 453.59237 g exactly, the conversion factors used for every unit change on this page.