A medium ear of corn on the cob has about 75 calories, making it one of the lighter starchy vegetables you can put on your plate. A full cup of boiled kernels comes in higher, closer to 155 calories, simply because you’re eating more corn. The exact number depends on the serving size, the variety, and what you put on top.
Calories by Serving Size
Most people eat corn either on the cob or as loose kernels, and the calorie difference between those two servings is worth knowing. A medium ear (roughly 6 to 7 inches long) contains about 75 calories. A larger ear, around 8 inches, lands closer to 88 calories. One cup of boiled, drained kernels, which is roughly what you’d cut off one and a half ears, has about 155 calories.
Air-popped popcorn, for comparison, has only about 30 calories per cup. That’s because popcorn is a different variety of corn with a much lighter, airier structure once popped. Sweet corn kernels are denser and hold more starch and water.
What Makes Up Those Calories
Corn is predominantly a carbohydrate. One cup of boiled kernels contains about 41 grams of carbs, 5.4 grams of protein, and very little fat. It also delivers roughly 4.6 grams of dietary fiber, which slows digestion and helps you feel full longer.
Corn has a glycemic index of 52, which puts it in the low-to-medium range. The glycemic load of a single medium ear is 15, meaning it causes a moderate rise in blood sugar. That’s comparable to foods like brown rice or sweet potatoes. The fiber content helps blunt any sharp spike.
How Toppings Change the Count
Plain corn on the cob is a relatively low-calorie food. The problem is that most people don’t eat it plain. A single tablespoon of butter adds about 100 calories and 11 grams of fat, more than doubling the calorie count of a medium ear. Grilling versus boiling doesn’t change the calories on its own, but grilled corn often gets brushed with oil or butter during cooking, which adds up quickly.
If you’re watching your intake, the simplest swap is using a light spread of butter on one side rather than rolling the whole ear, or seasoning with salt, pepper, and a squeeze of lime instead.
White Corn vs. Yellow Corn
Calorie-wise, white and yellow corn are nearly identical when you compare equal portions. Per 100 grams of raw kernels, yellow sweet corn has about 86 calories, and white sweet corn matches that almost exactly. The real difference is in one nutrient: vitamin A. Yellow corn gets its color from plant pigments called carotenoids, which the body converts to vitamin A. White corn contains virtually none. Yellow corn also provides significantly more lutein and zeaxanthin, two pigments linked to eye health. One cup of canned yellow corn contains over 2,000 micrograms of these compounds.
Canned, Frozen, and Fresh
The form you buy corn in affects the nutrition slightly. Fresh and frozen corn are nearly identical in calories because freezing preserves the kernel without adding anything. Canned corn can vary. Packed in water with salt, the calorie count stays similar, but some canned varieties include added sugar. Check the label for ingredients beyond corn, water, and salt.
Frozen corn that’s been boiled and drained provides about 1,129 micrograms of lutein and zeaxanthin per cup. Canned vacuum-packed corn actually delivers more, around 2,194 micrograms per cup, likely because the packing process concentrates the kernels. For basic calorie counting, though, fresh, frozen, and plain canned corn are all in the same ballpark.
Where Corn Fits in Your Diet
At 75 calories per ear, corn is lower in calories than a medium baked potato (about 160 calories) and comparable to a cup of cooked carrots. It sits in a middle ground between starchy and non-starchy vegetables. The fiber and protein content give it more staying power than, say, a slice of white bread with a similar calorie count.
One practical thing to keep in mind: corn is easy to overeat when it’s served as loose kernels in a bowl or mixed into dishes like casseroles and salads. A cup of kernels doesn’t look like much on a plate, but it’s nearly twice the calories of a single ear. Sticking with corn on the cob gives you a built-in portion control that makes it easier to keep track.