Why do clothing sizes differ from my baby's actual age?

Clothing sizes are approximate. Babies grow at different rates, so a 6-month-old may fit 3–6M or 6–9M clothes depending on their height and weight. Always check measurements rather than relying on age alone.

What is the difference between US and EU baby sizes?

US sizes use age ranges (Newborn, 0–3M, 3–6M, etc.) while EU sizes are based on body length in centimeters (50, 56, 62, 68, 74, 80, 86, 92). UK sizes typically follow the same age-range convention as the US but with slightly different cut tolerances.

My baby is tall but light — which size should I pick?

Always size for length first. Babies with long torsos or legs will feel restricted in a size that fits their weight. Look at the height column and choose whichever size accommodates their height.

When should I move up a size?

Move up when your baby's feet touch the footie ends of a sleepsuit, snaps are straining across the belly, or the neckline is hard to pull over their head. Buying half a size ahead gives comfortable room for growth.

Are brand sizes always consistent?

No. Size charts are industry guides; individual brands cut clothing differently. When in doubt, check the brand's own size chart and add a little extra room.

Baby Clothing Size Chart

Name: Baby Clothing Size Chart
Availability: InStock
Author: Nham Vu

Enter your baby's age, height, or weight to find the right clothing size in US, EU, and UK standards.

Find Size by Measurement

Baby's age

Full Size Chart

Newborn to 24 months — US, EU, UK

US Size	EU	UK	Height (cm)	Weight (kg)

Sizes are industry averages. Always check brand-specific charts, and size up for length when in doubt.

Summary

Enter your baby's age, height, or weight to find the right clothing size in US, EU, and UK standards.

How it works

Choose whether to look up by age, height (cm/in), or weight (kg/lb).
Enter your baby's measurement or select their age range.
The tool instantly shows the matching US, EU, and UK clothing sizes.
Use the full size chart below to compare all sizes at a glance.

Use cases

Find the right onesie or sleepsuit size for a newborn gift.
Shop international baby clothing brands that use EU or UK sizing.
Compare sizes when a baby is between two age brackets.
Quickly convert height or weight measurements to a wearable size.
Plan ahead and buy the next size up before your baby grows into it.

Frequently Asked Questions

Last updated: 2026-06-20 · Reviewed by Nham Vu