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All about the 0-3 months clothes size

Everything You Need To Know About the 0-3 Month Clothes Size

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It can be very difficult for parents to understand which size clothing their baby should be wearing and this starts with the 0-3 month clothes size.

The 0-3 month clothes size generally fits babies that weigh between 7 and 12.5 pounds and measure between 21 and 24 inches long. Although babies can typically wear the 0-3 month size from about the age of 2 weeks until 3 months, the fit will depend heavily on the size and shape of your baby.

Whether you are putting together your first baby registry (congratulations!), or just trying to figure out when you should switch what size your little one wears, keep reading for everything you need to know about your 0-3 month baby clothes.

When do babies wear 0-3 month clothes

I’m pretty sure there is no one who doesn’t love baby clothes. That may be an exaggeration, but only slightly. Whenever there is a new baby around, it seems like no one in my immediate (and sometimes not so immediate) family can go shopping without bringing home a tiny outfit that the baby “just needed.” Fortunately, my large family has enough experience with babies that they know to size up just in case, but for an inexperienced shopper, the sizing on baby clothes can be deceptively straightforward.

Babies typically wear 0-3 month clothes from about the time they are 2-3 weeks old until they are 2.5-3 months. Obviously this is very simplified because each baby’s birth size and development are unique. A newborn baby may be very long and skinny, which could lead to bodysuits fitting perfectly at one size, but that same size could be too short for a pair of footie pajamas from the same brand. On the other hand, some babies are chunky from the beginning and require the extra space of the 0-3 month size from birth.

Not only is each baby unique, but each brand of baby clothes also has its own variations in sizing and cut as well. I researched ten popular baby clothing brands and found that, with a few exceptions, the sizing charts tend to be comparable, but none are identical. 

Check out this chart that outlines the recommended height and weight for 10 of the most common baby clothes brands out there and then keep reading to learn more about your specific questions!

Height and Weight Chart for 0-3 Months Clothing Size

Brand0-3 month size minimum height0-3 month size maximum height0-3 month size minimum weight0-3 month size maximum weightSizing notes
Wonder Nation20.5"23"6.5lb12lbLarge size range between products
Gerber21"24"6lb12lbRun very small compared to other brands
Gap18"23"7lb12lbTrue to size
Old Navy19"23"7lb12lbTrue to size
The Children's Place20.5"24"7lb14lbTend to run small
Garanimals21.5"23"8lb12.5lbRuns a little large
Carter's21.5"24"9lb12.5lbConsidered the benchmark of 'true to size" by many
Burt's Bees Baby21.5"24"9lb12.5lbMore narrow than Carter's
Cat + Jack20.5"23.5"9lb12lbRuns a little large
Amazon Essentials21.5"24"9lb12.5lbTrue to size

How many pounds for 0-3 month clothes

Weight is a big factor for baby clothes sizing but it should be pointed out that a tall, skinny baby could weigh the exact same as a shorter, chunkier baby so it doesn’t tell the whole story.

Baby clothes in the 0-3 month size typically fit infants as small as 7 pounds up to 12-12.5 pounds. The best way to tell if a 0-3 month size outfit will fit your child properly is to consult the sizing chart on the brand’s website.

Gerber 0-3M baby clothes fit infants as small as 6 pounds (and up to 12 pounds) and are generally considered to run small. 

Several brands, including Gap, Old Navy, and The Children’s Place fall into the middle range and fit a 7-12 pound baby, although some parents still report that these run small.

Despite being on the larger end of 0-3 month sizing at 9-12 pounds, Carter’s clothes are among the brands that are considered “true to size” overall. I can’t say for certain, but I suspect it has something to do with the ubiquity of the Carter’s brand and the number of lines it encompasses. 

How many inches for 0-3 month clothes

Your baby’s weight is not the only indicator of what size he will wear, however, and his length should also be taken into account.

Most 0-3M sizes are meant for a baby who is between 21 and 23 or 24 inches. A one-inch variation in size may seem insignificant, but could potentially mean an entire extra month of wear time.

There is more overlap in brand sizes as far as length than there is weight, but it is worth examining both metrics carefully if you are having trouble finding clothes that fit your baby properly. Just like not every pair of jeans you try on will fit you perfectly, not every clothing brand is right for your baby’s body and development.

How long do babies stay in 0-3 month clothes

There is no specific age at which your baby will outgrow his 0-3 month clothes, but it may very well be before he’s even three months old. Just like with his tiny newborn sized outfits, it will probably feel like your baby wears his 0-3 month clothes for no time at all, in fact, don’t be surprised if he outgrows them before he even makes it to the three-month mark.

There are a huge number of variables that go into determining how long your baby will wear his 0-3 month clothes — birth size, gender (boys tend to develop a little faster in the first three months of life, whereas girls get their growth spurts between 3 and 6 months), brand sizing — but the average baby will probably wear Carter’s (an average brand) 0-3M clothes from about the time he’s two weeks old until he’s 2 and a half months old.

How many 0-3 month clothes do I need

As with so many things involving your baby, how many clothes you need will be determined heavily by how often you plan on doing laundry. For each day, you should plan on having at least two outfits plus pajamas. During the winter months, you should plan on having an extra layer for each day. Personally, I always assume that I will be behind on the laundry and try to account for an extra day or two just in case.

For example, if you plan on doing laundry just once a week, you may need as many as 24 outfits (I say outfits, but at this age, that often just means a bodysuit, especially if you swaddle at night). If you can manage to wash laundry twice a week, you should be able to save a lot of drawer space by only buying 12-15 outfits. Since the clothing is so small, you can usually do all of baby’s laundry in one load too!

Those tiny little outfits may be absolutely adorable, but I find that having just a couple of “going out” outfits and a bunch of plain white workhorse bodysuits is perfect for this age – and much easier on the wallet.

Can a newborn fit into 0-3 month clothes

The average baby is between 19 and 20 inches at birth — with a standard range varying from 18 to 22 inches — and 7 pounds, 5 ounces, but is not uncommon for even completely healthy full-term babies to be smaller, and many newborns are much larger. If your baby is born fitting into the 0-3 month size, go ahead and put them in it. 

When to switch from newborn to 0-3 month clothes

It can be hard to tell when to go up a size in your baby’s clothing, especially for a new parent. Your baby’s clothing is similar to yours in that you want it to fit comfortably and not be so tight that it cuts in or chafes anywhere, but not loose enough to be baggy. Keep in mind that baggy clothes on you may be unflattering, but they can be a major choking or suffocation hazard for a small baby, so all clothes should be snug, but not tight fitting.

Since your doctor will give you your baby’s measurements and his developmental percentile at his two-month appointment, this is a perfect time to make note of whether or not you will need to be sizing up soon just based on the numbers.

I’ll be honest though, even if you’re new at this, you will probably be able to look at your baby and know if the time has come to retire an article of clothing and bring out the next size up.

Joshua Bartlett
Joshua Bartlett

My name is Joshua Bartlett I run this blog with my wife Jarah. We have more than 11 years of parenting experience including three girls and one boy. I started this blog in late 2018 when I realized that I was dealing with baby-related issues on a constant basis…please read more about me here!

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