Average Weight for a Newborn Boy

The average (50th-percentile) weight for a newborn boy is 3.3 kg (7.4 lb), based on the WHO Child Growth Standards. Across the healthy range, most boys this age weighs between 2.5 kg (5.5 lb) and 4.3 kg (9.6 lb).

What's typical at this age

Newborns commonly lose up to 7–10% of their birth weight in the first few days, then regain it by about two weeks. Feed on demand and let your baby's cues, wet nappies and mood guide you more than the scale. In the first month, the median boy gains roughly 1125 g.

A percentile compares your boy to other boys the same age — the 50th is simply the middle. Being above or below it is usually completely normal; a baby who has always tracked the 15th or 85th percentile is typically growing exactly as they should. What pediatricians watch for is a sudden change in the pattern, not the number itself.

Percentiles calculated from the WHO Child Growth Standards (2006). For information only — not medical advice. If you're concerned about your child's growth, speak to your pediatrician or health visitor. Full disclaimer.