Preemie vs Newborn Clothing Sizes

newborn clothing

It’s time to go shopping for clothes for your new baby, but the sizing can be confusing. Your newborn may well need preemie, newborn or 0-3 month old clothing sizes, so how do you know which one is best?

Preemie clothing is for babies who weigh up to 5-6lbs and who are up to 18 inches in length. On average, newborn clothing is for babies who weigh 5-8lbs and who are up to 21.5” in length. Let’s have a look at preemie versus newborn clothing and get to the bottom of what the sizing means and what things you should consider.

Can newborns wear preemie clothes?

Yes, they certainly can if the preemie clothes fit them well. A baby born after 37 weeks who was not premature (born after 37 weeks) might still need to wear a smaller size. It just depends on the baby, their proportions and how the clothes themselves come up for each brand. Look beyond the words on the label and buy the size that fits your baby best. It might take some time to find the size and brands you like.

What is preemie size clothing?

Preemie is short for premature which means a baby who is born before 37 weeks of pregnancy. Preemie size clothing is designed for babies who are born prematurely and are likely to be a bit smaller than most newborn babies. Stores that carry baby clothing usually stock preemie size clothing but may have limited designs and small stock numbers. Just be prepared to shop around a little bit to get the sizes and styles you want. Of course, with the shopping world at our fingertips it is easy to find a wide range of options online as well. In most retailers preemie clothing is for babies who have a low birth weight of around 5-6lbs and who are up to 18” long.

What age is a baby considered a preemie?

According to the CDC a baby is considered premature, or a preemie, when they are born before 37 weeks of pregnancy. This is because after 37 weeks most babies are considered full-term, are fully developed and are less likely to need medical support once they are born. A baby who is premature may need additional medical support after birth and is likely to be smaller in size.

How long can preemies stay in newborn clothing?

Preemies can stay in newborn clothing as long as it fits them, yet you are likely to find that your baby won’t be in newborn clothing for too long. You can expect them to wear newborn clothing for 3-6 weeks depending on the brand of clothing and your baby’s size. Your baby might not quite be a newborn by the time they get into the newborn size though, so look at the height and weight suggestions on the label to guide you. 

Is there a preemie size in the UK and Europe?

Yes there is a preemie size in the UK and Europe and it is widely available in most mainstream stores and online. However, not all preemie size clothes measure up the same and of course the size of preemie babies varies a lot. The generic preemie size you are likely to find on the rail is aimed at babies who weigh 5-8lb. You might see this size labelled as “tiny baby” rather than preemie so keep an eye out for that when you are shopping in the UK or Europe.

You will find shopping online to be best for any smaller sizes of clothes for your preemie. There are companies who design clothing for little ones who weigh as little as 1lb that may suit your needs.

Are there clothes smaller than preemie?

There are clothes that are smaller than preemie size for babies who are born especially early. You will have the best luck finding options for very small babies online and the sizing starts from around 1lb. There is clothing out there intended for babies who start their days in an incubator with special designs to not only fit them, but also to put them in with the greatest ease.

What should a preemie wear to sleep?

The best advice to dress your preemie for sleep is to put them in layers that you can easily take off or add to as their temperature adjusts. It is recommended that preemies wear a onesie and sleep suit and then a zip up sleep bag. Preemies should not wear a hat when they sleep to avoid them overheating.

You can always add or take away clothing as your baby sleeps so have an extra layer close to their crib or bassinet. It’ll save you running around the house in the middle of the night should you need an extra layer!

What size is newborn clothing?

Newborn clothing is generally designed for babies around 5-8lbs and around 21 inches in length. In reality, every brand will come up a bit differently and each baby will be proportioned uniquely too. This means that one newborn outfit may fit your baby just right and another one may be way too big or too small. Be prepared to shop around and try out different styles.

Can newborns wear 0-3 month clothing?

Newborns can wear 0-3 month clothing right away and most parents actually find that this size lasts a lot longer than newborn clothing. In addition, if your baby is born weighing over 8lb you will find that the newborn size won’t last very long and the 0-3 month size will be your go-to option. Some newborns jump right into 0-3 month clothing and bypass the newborn size completely. Others stay in the newborn size for a while longer.

We did this with our son, who had an above average birth weight. He skipped the newborn size completely!

How long will newborns typically wear newborn size clothing?

There is no set answer to how long newborns will typically wear newborn clothing because all babies and clothing brands are different. The general guide though is that a baby who weighs less than 8lb at birth will wear newborn clothing for 4-6 weeks. Meanwhile a baby who weighs more than 8lb at birth will only be in newborn clothing for 3-4 weeks, if at all.

What do newborn babies wear?

There are lots of outfit options for your newborn baby to wear including formal outfits with tights, shirts and more. This is a valid choice for you and your baby and some people choose to pick different styles and outfits from the get go. Alternatively, many parents opt instead for a simple rotation of onesies, sleep suits and simple legging style pants. Newborns tend to go through outfits quickly and between the spit up and diaper leaks you will end up changing them a lot.

Layers are the way to go to keep your baby comfortable and the climate where you live will determine how many you need. A general rule of thumb is that babies should only wear one more layer than you to avoid overheating. Babies do not need to sleep in a hat and do not really need shoes either until they start walking. 

What clothing sizes do you need for a newborn baby?

The clothing sizes you need for a newborn baby depend somewhat on when your baby is born. A preemie will need smaller sizes than the average baby born after 37 weeks of pregnancy. A baby born over 37 weeks will probably need some newborn size clothing and then more 0-3 month size clothing. Most babies get more wear out of the 0-3 month size than the newborn size so it may be worth investing in more of the larger option. Again, this really does vary based on your baby’s needs.

Remember, you can always roll up the cuffs of your newborn’s pants and a slightly bigger onesie will be fine. As long as they aren’t swimming in an outfit it is okay for it to be a little big on your baby!

What are newborn sizes in the UK and Europe?

Newborn sizes in the UK and Europe are designed to fit babies up to 10lb in weight and 56cm in length.


A great rule of thumb when it comes to shopping for your newborn is that you can always add to their wardrobe and buy more clothes after they arrive. Start with a core selection and then add to it. It is not possible to plan exactly how big your baby will be when they are born and which clothes in each size they will fit into. It’s a smart move to invest in some newborn and 0-3 size clothing before your baby is born and know you can always purchase more pieces, or pick up preemie options. The good news is that your baby will be adorable no matter what you put them in!