Corn Kernels

One US cup of corn kernels weighs 136 grams (4.8 ounces), measured frozen, straight from the bag. Going the other way, 100 grams is about 0.74 cups.

Also called sweet corn kernels, frozen corn, frozen corn kernels, fresh corn kernels, whole kernel corn, corn off the cob.

Chopped vegetables compared: cup weights side by side, the source behind each, and why they differ.

A cup of frozen corn kernels weighs 136 g (4.8 oz) measured straight from the bag, and a cup of fresh kernels cut from the cob 145 g (5.1 oz). USDA weighs both; the Birds Eye, Cascadian Farm and Great Value labels agree with the frozen figure, and USDA's survey database and King Arthur with the fresh one. King Arthur's 152 g, given for fresh or frozen, agrees for fresh kernels and is heavy for frozen.

Sweet corn is picked young, while the kernels are still soft and sugary; USDA puts raw yellow sweet corn at 76% water, 19% carbohydrate, 3% protein and 1% fat. Frozen corn is cut from the cob, blanched and frozen loose, so each kernel stays separate. That is what makes frozen and fresh measure differently: frozen kernels are hard and do not settle, while fresh-cut kernels are moist, sometimes still joined in rows, and slump into the gaps.

For frozen corn, USDA SR Legacy "Corn, sweet, yellow, frozen, kernels cut off cob, unprepared" (FDC 168398) lists 1 cup at 136 g. Birds Eye's Steamfresh Super Sweet Corn label gives 2/3 cup at 95 g, measured frozen, as does Cascadian Farm's, both 142.5 g per cup, and Great Value's gives 2/3 cup at 90 g, 135 g per cup. All four are within 6% of each other. Green Giant prints 2/3 cup at 84 to 85 g and Kroger 1/2 cup at 85 g; 85 g is the reference serving for vegetables and the volume beside it is the nearest household measure, so those pairs are not read as densities.

For fresh kernels, USDA SR Legacy "Corn, sweet, yellow, raw" (FDC 169998) lists 1 cup at 145 g and USDA's survey database (FNDDS, FDC 2709783) 150 g. King Arthur lists corn, fresh or frozen, at 1/4 cup = 1 1/3 oz = 38 g, 152 g per cup, within 5% of both.

The physical check: corn kernels are a little denser than water, so a cup at 136 to 163 g is somewhere between half and two thirds corn, the rest air. Hard frozen kernels leave the most gaps; once thawed they settle. USDA's school Food Buying Guide counts a pound of frozen corn at about 2 3/4 cups of thawed kernels, 163 g per cup, and the Culinary Institute of America gives 1 cup of kernels at 163 g. That is why one figure cannot be right for fresh and frozen alike: King Arthur's 152 g sits between frozen and thawed, and matches fresh.

Canned corn is another measure again. USDA's drained canned whole kernels weigh 164 g per cup, and the Food Buying Guide's drained canned corn about 195 g; labels that include the packing liquid run higher still.

Practical guidance: measure frozen corn frozen, straight from the bag, at 136 g per cup; a 10-oz package, 284 g, is a little over 2 cups. For fresh corn, a cup of kernels is 145 g. If a recipe was written with thawed corn, expect a cup to hold about 163 g. For cornbread, salsa and chowder, where a little more or less corn does no harm, cups are fine; where the corn's moisture matters, as in fritters, weigh it.