InfoPlease explains that human skin weighs between  8 to 10 pounds in normal adults, with around 22 square feet of area. The skin is the largest organ in the body in terms of weight and area. One of the smallest organs in the body, the pineal gland, weighs around 0.2 gram, or 0.007 ounce. The pineal gland is in the center of the brain, according to Kids Discover. The parathyroid is between 0.004 and 0.006 ounce, or 0.12 to 0.18 gram.