Baby Clothing Size Guide: How to Pick the Right Size by Age and Height

Baby clothes are labelled by age, such as “3–6 months”, but babies of the same age can be very different sizes. The label is a starting point; your baby’s height and weight are a better guide.

Start with height

Many brands size baby clothes by height. These are the common ranges. Treat them as approximate, because every brand cuts a little differently.

Sizes are a general guide only. Always check the size chart on the product page.

How to measure

1. Lay your baby on a flat surface and measure from the top of the head to the heel.
2. Note your baby’s latest weight from the clinic or a home scale.
3. Compare both with the product’s size chart, not just the age label.

Between two sizes? Size up

Babies grow quickly, and clothes that are a little roomy last longer and are more comfortable. Choose the bigger size when your baby falls between two, and fold the sleeves or legs for now. Very tight clothes can leave marks and are hard to put on.

Tips for imported clothing

• Clothes made in Asia often run smaller than European or American labels. Read the centimetre measurements, not just the age.
• Check the size chart in the description, and compare it with a garment your baby already wears well.
• Buy a size up for outerwear, sleepsuits and anything that should be loose to wear over a layer.

What else to check

• Soft, breathable fabric (cotton is a common choice) against the skin.
• No hard buttons, long strings or loose decorations that could come off.
• Wide neck openings or snap fastenings for easy dressing.
• Wash new clothes before the first wear.