When asking how much does the human heart weigh in pounds, it varies based on who the person is, and whether or he or she is healthy. In some cases, the care can enlarge and be significantly abnormal in size. Doctors look for this, as well as its overall function, to determine health. The mass of a healthy heart is about 300 grams, which is equal to about 0.661387 of a pound. It is still considered healthy with a weight of 425 grams, or 0.936965 pounds, in some cases.