Average Weight for a 13-Month-Old Boy

The average (50th-percentile) weight for a 13-month-old boy is 9.9 kg (21.8 lb), based on the WHO Child Growth Standards. Across the healthy range, most boys this age weighs between 8.0 kg (17.7 lb) and 12.1 kg (26.7 lb).

What's typical at this age

Toddlers grow more slowly than babies, and appetite often drops with it — this is normal. Fussy eating is extremely common; offer variety without pressure and trust their hunger cues. Between month 13 and month 14, the median boy gains roughly 220 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.