Baby clothing sizes can be confusing, especially when you're shopping before the baby is even here. You see Preemie, Newborn, 0–3 Months... but how are you supposed to know which one you'll actually need? And if it's your first baby, you may be wondering how much of each size you should have ready.
The truth is, you don't really know exactly how your baby will fit into clothes until they're here. Babies can be born at very different weights, and the size written on the tag is only a starting point.
Preemie, Newborn and 0–3 Months - What's the Difference?
One thing I think is important to know is that baby clothing sizes aren't exactly the same from every brand. That's why I always prefer looking at the weight range instead of only looking at the age on the label.
At Baby Fil, our sizes are based on the following weight ranges:
Preemie: 3-6.5 lb
Newborn: 6.6-9 lb
0-3 Months: 9-15 lb
If your baby is between sizes, we recommend sizing up for a more comfortable fit.
What If Newborn Size Is Too Big?
When we're preparing for a baby, most of us automatically think about Newborn and 0-3 Months. But not every baby arrives fitting comfortably into Newborn clothes. For some babies, even Newborn size can be too big at first. That's one of the reasons having a Preemie option was important to us at Baby Fil.
I think sometimes people hear the word Preemie and immediately think only about babies who were born very early. But when it comes to clothing, the baby's actual weight is what matters for choosing the right size. If a baby is under the weight range for our Newborn size, our Preemie size may simply provide a better fit.
Of course, if your baby is receiving hospital or NICU care, clothing may be a completely different situation and it's always best to follow what their care team recommends.
Should You Buy Newborn Size Before the Baby Is Born?
Personally, I would.
I know you'll often hear people say, "Don't buy Newborn. They'll grow out of it immediately." And yes, babies grow incredibly fast. But I still wouldn't want to have only 0–3 Month clothes waiting at home. If your baby is around 7 or 8 pounds, for example, a 0-3 Month footie made for a much larger weight range may have a lot of extra room. At the same time, I wouldn't fill an entire drawer with one size either.
Having a few pieces in Newborn and some in 0-3 Months gives you options. If you know your baby may be smaller, having a couple of Preemie pieces ready can also make sense.
What About Buying a Baby Gift?
I think this is where choosing the size becomes even harder because you don't know exactly how big someone else's baby will be.
If I'm buying something specifically for the baby's first days and I know their approximate birth weight, I would use that to choose the size rather than automatically buying 0-3 Months. If I don't know, 0-3 Months gives the parents more time to use the gift. But there's also something nice about receiving an outfit that actually fits the baby right away instead of putting it away for later.
This is one of the reasons we offer Baby Fil pieces in Preemie, Newborn and 0-3 Months. Babies don't all arrive the same size, and I wanted parents and gift-givers to have options.
How Long Will a Baby Wear Each Size?
This is probably the question with the least exact answer. Some babies will move through a size very quickly. Others will stay in it much longer. And growth doesn't happen according to the number printed on a clothing tag.
Instead of worrying too much about age, look at how the clothes actually fit. If a footie is becoming tight, there's pulling around the body or feet, or your baby doesn't have enough room to move comfortably, it's probably time to size up. And if your two-week-old is already wearing 0–3 Months? That's completely fine too.
So, Which Size Should You Buy?
If you're preparing before birth, I wouldn't try to predict everything perfectly.
Have a few pieces ready in the size you expect your baby to need, and have the next size waiting too. Look at weight ranges when you shop, because they're much more useful than assuming every baby will fit a certain size at a certain age. And don't buy too much of one size before you know what works.
I learned pretty quickly as a mom that babies have their own plans when it comes to how fast they grow. You can have a drawer perfectly organized by size and somehow they'll still grow out of something before you even remember they had it. 😅
Preemie, Newborn or 0-3 Months? The best size is simply the one that fits your baby comfortably right now.