0 Votes. Bald eagles can grow to a body length of 28–40 inches, a wingspan of up to 96 inches, and a weight of 5.5–15 lb. Females are usually 25% larger than males. The largest bald eagle nest on record was 9.5 feet wide and 20 feet high.It weighed more than two tons.emale bald eagles are larger than males. The average length for bald eagles is 31 inches, the average wingspan is 80 inches, and their average weight is about 9.5 pounds. Bald eagles do not actually get their bald or white head and tail until they are about 4 to 6 years old. National Audubon Society.