Question: 12 month baby is how old?
Answer: 1-Year-Old Weight & Height The average weight for a 1-year-old baby is 21.9 pounds for girls and 21.3 pounds for boys. Average height (formerly known as length) is 29.1 inches for girls and 29.8 inches for boys. Baby's probably tripled her birth weight and is about 10 inches longer than she was at birth.