Crumbs and cereals in grams: bread crumbs, panko, cookie and cracker crumbs, corn flakes, crisp rice and Grape-Nuts compared

A US cup of crumbs or breakfast cereal can weigh four times as much as another: 28 grams for corn flakes or crisp rice, more than 110 grams for chocolate cookie crumbs or Grape-Nuts. What decides it is how much of the cup is air, which depends on the shape of the pieces and how finely they are crushed.

All weights are for a US cup of 236.5882365 ml; a tablespoon is a sixteenth of it and a teaspoon a forty-eighth. The scale puts every figure on one axis of grams per cup. A range means the sources disagree by more than this site’s tolerance for that kind of ingredient, so no single figure is chosen. King Arthur’s figure is shown where this site records one, with the verdict on it. Each ingredient’s own page has every source and the full reasoning.

Flaked and puffed cereals are among the lightest things measured by the cup. Corn flakes are thin curled sheets and crisp rice is hollow puffed grains, and a cup of either weighs about 28 grams, an eighth of the weight of a cup of water; USDA, America's Test Kitchen, King Arthur Baking and the makers' labels agree within a few percent. Bran sticks, short and dense, weigh 62 grams a cup, and Grape-Nuts, small hard nuggets that pour like sand, 116 grams, about as much as a cup of flour.

Crumbs follow the food they were made from. Light, airy vanilla wafers crush to about 80 grams a cup; graham crackers, denser and usually ground fine, to about 102; dense chocolate wafers to 112, and fine machine-made chocolate baking crumbs to about 126. Dried bread crumbs weigh 108 grams a cup, and panko, made as coarse airy flakes, about half that.

Fineness matters as much as the food. USDA weighs a cup of crushed snack crackers at 52 grams, and Nabisco's machine-crushed Ritz crumbs weigh 81 grams a cup, half again as much, because fine crumbs nest into each other's gaps while hand-broken flakes prop each other up. Corn flakes show the same thing from the other side: Kellogg's own recipes treat 4 cups of whole flakes as 1 cup of its ready-made crumbs, so a recipe that asks for a cup of crushed flakes needs about four cups of whole ones.

Measure crumbs and cereal loosely, spooned or poured into the cup and levelled without pressing. For crusts and coatings, weigh: a crust that calls for 1 1/2 cups of crumbs needs about 120 grams of vanilla wafer crumbs but about 170 grams of chocolate ones, and pressing either into the cup adds more still.