Blood donors must weigh at least 110 pounds, as stated by the American Red Cross. For donors who are 18 years old and younger, the weight requirement is dependent on height.
Males who are 18 years old or younger and at least 5 feet tall must weigh 110 pounds, but males who are 4 feet, 11 inches tall must weigh at least 114 pounds, according to the American Red Cross. Young women who weigh 110 pounds must be at least 5 feet, 6 inches tall, and weight requirements increase for those who are 5 feet 5 inches tall and shorter. Blood donors must be in good health and feeling well on the day of the donation, and they need to be at least 17 years old. Some states allow 16-year-olds to donate with a signed parental consent form.