Average Weight & Length for a 9-Month-Old Baby

Growth at 9 Months

By 9 months, babies have typically tripled their birth length gain since birth. The average 9-month-old boy weighs about 9.5 kg (20.9 lb) and measures 72.3 cm (28.5 in). Girls average 8.7 kg (19.2 lb) and 70.6 cm (27.8 in). Growth continues at a moderate, steady pace.

Physical Development at 9 Months

Nine-month-olds are usually crawling, sitting independently, and may be pulling to stand. They're developing their pincer grasp (picking up small objects between thumb and forefinger) and may show stranger anxiety. This is a critical period for both motor and cognitive development — track milestones with our milestone tracker.

Feeding at 9 Months

By now, most babies are eating a variety of solid foods alongside breast milk or formula. Three meals per day with 1–2 snacks is typical. Babies are learning to self-feed with finger foods. Adequate nutrition supports the steady growth seen at this age.

The 9-Month Well-Child Visit

The 9-month checkup is an important milestone visit where your pediatrician will measure weight, length, and head circumference, screen for developmental milestones, and discuss feeding. Use our growth dashboard to review your baby's measurements before the visit.