One cup of unpopped popcorn kernels contains 225 grams, or 8 ounces of the kernels. Use 1 tablespoon of kernels for 1 cup of popcorn; 2 tablespoonfuls produce between 2-1/2 and 3 cups. The number of kernels in one tablespoon varies with the size of the kernels.
The amount of finished product from any given number of kernels often differs depending on variety. Yellow corn pops up "bigger" than white, whereas white popcorn is more tender; its hull is thinner and spreads out more evenly. The amount of popcorn yielded from raw kernels also depends on moisture content, freshness, and the popping method used.