If you've ever bought a "12-month" outfit for a 9-month-old and had it not fit, you already know: age labels on kids' clothing are a rough approximation at best. Height and weight are far more reliable.

Babies (0–24 Months)

Label Age Height (cm) Weight (kg)
Newborn 0–1m 50–56 2.5–4.5
0–3m 0–3m 56–62 4.5–6
3–6m 3–6m 62–68 6–8
6–9m 6–9m 68–74 8–9.5
9–12m 9–12m 74–80 9.5–11
12–18m 12–18m 80–86 11–12.5
18–24m 18–24m 86–92 12.5–14

Toddlers (2–4 Years)

Label Height (cm) Weight (kg)
2T 86–92 12–14
3T 92–98 14–16
4T 98–104 16–18

Kids (4–12 Years)

Label Age Height (cm)
4 4y 98–104
6 5–6y 110–116
8 7–8y 122–128
10 9–10y 134–140
12 11–12y 146–152

Brands vary — always check the height/weight chart printed on the brand's own size guide when possible.

Why Age-Based Sizing Fails So Often

Children grow at wildly different rates. A "tall for their age" 4-year-old might need a size 6, while a petite 6-year-old might still fit a size 4. Buying by age alone ignores this entirely, which is why returns and exchanges are so common for kids' clothing gifts.

Tips for Buying Gifts for Kids You Don't See Often

  • Ask a parent for the child's current height and weight rather than just their age — most parents know this off the top of their head from recent doctor visits.
  • When in doubt, size up. A slightly large outfit gets worn longer; a too-small one gets returned immediately.
  • For shoes, don't size up by more than half a size — overly large shoes can affect how young children walk and balance.
👶 One profile per child, updated as they growParents can keep a running Size Notes profile for each child — current height, weight, clothing size, and shoe size — and share it with grandparents, aunts, uncles, and godparents so every gift fits, every time.

The Bottom Line

For kids, age is a starting point, not the answer. Height and weight measurements — updated every few months — will get you a far more accurate size than a birthday alone ever could.