A 1-pound bag of long-grain white rice contains approximately 21,000 to 25,000 grains of rice. There are approximately 48 grains in 1 gram, according to FreeRice. Since there are 453.6 grams in a pound, the total number of grains is 21,773.
According to the U.S. Rice Producers, about 228 grains of rice are contained in 1 teaspoon. With 24 teaspoons contained in 1/2 cup, there are approximately 5,472 grains of rice in each 1/2 cup. A 1-pound bag of long-grain white rice contains about 2 1/4 cups. This method of calculation suggests that there are about 24,624 grains in a bag.
The number of grains varies according to the type of rice. Bags of short-grain rice contain more grains than bags of long-grain rice, and bags of Basmati rice contain more grains than bags of long-grain rice.