Lowdown on baby clothes sizing

Understanding baby clothes sizing isn't always clear cut, this guide is here to help

Baby clothes: Your essential guide to sizes

Clothes sizing for your newborn can vary depending on your baby's birth weight, this size guide can help you understand what sizes are best for your baby

Pregnant woman shopping for baby clothes

The Lowdown

Buying clothes for your baby is an enjoyable part of becoming a parent, but when you first are faced with such a multitude of choice it can become a little confusing!

Never buy too much clothing in one size as babies grow very quickly, especially in their first year. Many people will also buy you baby clothes as presents, but they usually choose the small sizes that won’t fit for long, so make sure you keep that in mind.

Buying just what you need means that you’ll always need to have a wash on, but most baby clothes are designed to withstand countless times through the washing cycle and it means less waste, too!

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What to look for

Always be guided by your baby’s height and weight rather than by their age when choosing clothes. When shopping, always choose clothing in one size ahead of your baby’s actual age so you get extra wear out of them. Most six-month-old babies can wear clothes in size 9–12 months, for example. 

If you're buying for your unborn baby, in general it’s best to buy 0-3 month clothes, as newborn size can be outgrown very quickly.  It’s important to never dress them in clothes that are much too big though, especially sleepwear. It could be a suffocation risk.

Need to know

Sizes do vary slightly from brand to brand, so always check the label or packaging before you buy to see what fits your baby best. Another tip is to keep labels and packaging attached until it's time for your baby to actually wear an item, especially if you've bought it weeks in advance, so it can be easily returned if it doesn't fit properly. 

Remember these measurements are a guide only - always check individual labels before you buy.

Early baby
Weight 7.5lb/3.4kg
Length 50cm

Weight 10lb/4.5kg
Length 56cm

0-3 months
Weight 14.5 lb/6.5kg
Length 62cm

3-6 months
Weight 17.5lb/8kg
Length 68cm

6-9 months
Weight 20lb/9kg
Length 74cm

9-12 months
Weight 22lb/10kg
Length 80cm

12-18 months

Weight 24lb/11kg
Length 86cm

18-24 months
Weight 26lb/13kg
Length 92cm

Lowdown on baby clothes sizing