Baby Clothing Size Predictor
Enter your baby's age, weight, or height to find their recommended clothing size. Covers Preemie through 5T with brand comparison notes.
Enter at least one value. Weight and height give the most accurate result.
Enter your baby's info to find their size
Age alone works, but adding weight or height makes it more accurate
Standard US Baby Clothing Sizes
| Size | Age | Weight (lbs) | Height (in) |
|---|---|---|---|
Preemie | Premature | Up to6 | Up to17" |
Newborn | Newborn | 6–9 | 17–21.5" |
0–3M | 0–3 mo | 9–12.5 | 21.5–24" |
3–6M | 3–6 mo | 12.5–17 | 24–27" |
6–9M | 6–9 mo | 17–21 | 27–28.5" |
9–12M | 9–12 mo | 21–25 | 28.5–30" |
12M | 12–15 mo | 21–25 | 28.5–30" |
18M | 15–21 mo | 25–28 | 30–32" |
24M / 2T | 1–2 yr | 28–30 | 32–34" |
3T | 2–3 yr | 31–33 | 35–38" |
4T | 3–4 yr | 34–38 | 38–41.5" |
5T | 4–5 yr | 38.5–43 | 41.5–44" |
Based on Carter's / OshKosh sizing, the most widely used standard in the US. Sizes vary by brand — see brand notes below.
How Sizes Vary by Brand
Gerber
Runs small. Many parents size up 1–2 sizes. Gerber Preemie fits up to 5 lbs (vs 6 lbs at Carter's) and Newborn fits 5–8 lbs (vs 6–9 lbs).
Carter's / OshKosh
True to size and the de-facto US standard. Fits longer, leaner babies well. Our chart above is based on Carter's sizing.
Cat & Jack (Target)
Runs slightly generous. Good for chunky babies. Similar ranges to Carter's but more room in the width.
Honest Baby / Burt's Bees Baby
Organic cotton tends to run snug and may shrink after washing. Consider sizing up one size.
Always check the brand's own size chart. When in doubt, go by your baby's weight and height rather than age.
Shopping Tips
Buy a size up
Babies grow fast — especially in the first year. If your baby is near the top of a size range, skip to the next size. Slightly loose clothes are comfier and last longer.
Plan for the season
A baby born in summer who wears Newborn now might need 6–9M by winter. Buy ahead for the weather they'll experience in each size, not the weather right now.
Don't stock up on Newborn
Most babies outgrow Newborn size within 2–4 weeks. Stock up on 0–3M instead — that size gets the most wear.
2T vs 24M
Both fit the same weight and height, but 24M is cut for diapers (roomier bottom) while 2T assumes potty training (slimmer). Pick based on where your toddler is.
Cotton shrinks
100% cotton clothes can shrink up to 5% after the first wash. Pre-wash before deciding if a size fits, or account for shrinkage when buying.
Weight over age
A chunky 4-month-old might wear 9M, while a petite 4-month-old wears 0–3M. Always go by weight and height when the label age doesn't match your baby.
Sizes are based on industry standards from Carter's, Gerber, and other major US brands. Every baby is different — use weight and height for the best fit.
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