Understanding baby clothes sizes is a challenging task for new parents. There are ages and weights and it can get quite confusing when you’re searching for your baby’s correct clothing size! This guide will explain everything you need to know about baby clothes sizing: understanding fit, interpreting size charts and what to do if baby clothes don’t fit your little one.
How Do Baby Clothes Sizes Work?
Baby clothes sizes in North America are sold by age but fit according to the baby’s weight and height.
So while your infant may be 2 months old, it’s possible that they’re big enough to fit into the 3-6 month size. Alternatively, your 2-month old may have been born on the smaller end of the chart and still fit into the newborn size.
Babies reach each clothing size at different times depending on their size at birth, their growth rate, and the brand of clothing you select. This will also impact how long your baby will remain in each size before sizing up. I go into more detail about this here: How Long Do Babies Wear Newborn Clothes?
Most stores have the following sizes available: newborn (NB), 0-3 months (3M), 3-6 months (6M), 6-9 months (9M), 12 months (sometimes seen as 9-12M or 6-12M), 12-18 months (18M), and 18-24 months (24M). Certain brands also offer preemie (PRE) and micro-preemie (MP) sizes.
As you can see, the newborn size is not the same as 0-3 months. This causes a lot of confusion for many new or expecting parents. The 0-3 month size is larger than the newborn size (even though some newborns skip past the NB size and are born already fitting into 0-3M clothes!).
Once your baby has outgrown the 24M size, they will move into the toddler clothing section.
Garments of each of the sizes mentioned, tagged by age, follow a size chart based on the baby’s weight and height.
While it would be very convenient for all brands to follow the same size chart, that’s not quite how it works. Even newborn sizes can vary from store to store.
To understand your baby’s size, you’ll need to do a little experimenting to find out how individual brands fit on your little one’s body.
There are the size charts for many popular clothing brands, including Carter’s, GAP, and Gerber, displayed at the bottom of this article.
How to Know Your Baby’s Clothing Size
To know the size of clothes a baby needs, you will first need to know their approximate height and weight. From there, you can narrow down the size. Since brands vary in the fit of their apparel, you may still need to go through a bit of trial and error to find the ideal size for your infant.
When expecting parents are purchasing clothing for their unborn baby, it’s nearly impossible to know the size that their baby will be at birth. Ultrasounds can offer you an estimate of the baby’s weight and length, but even that isn’t 100% accurate in predicting the size that the baby will be born.
New parents should always be ready with a couple of different sizes for their newborn, especially size newborn and 0-3 months.
Once your baby has been welcomed into this world, you’ll have a good idea of how much they weigh and their approximate length. As you start dressing them in all their adorable infant clothes, you’ll become very familiar with how their current size is fitting.
If you notice waistbands getting too snug or pajamas that are fitting too short, it’s probably time to move up to the next size.
As I mentioned, an important tip for parents is to buy clothes based on size or fit, not age! While clothing sizes are categorized by baby months, there’s a good chance your infant will not be fitting into the “correct” month at the correct time.
How Should Baby Clothes Fit?
Baby clothes should always fit comfortably! That’s how.Babies shouldn’t be constrained in their clothes nor drowning in fabric.
They should be able to stretch and wiggle and move around freely as babies do without dangling sleeves or overly bunching material.
Baby clothes should be breathable, stretchy and comfortable for their little bodies. More on the best way to dress a newborn here!
What to Do if Your Baby is In Between Clothing Sizes: When to Move Up a Size in Baby Clothes
Many new parents may wonder what happens if their baby is in between two sizes. What if your little one is getting a bit too big for the newborn size but 0-3M is fitting a little long or loose?
Related Article: How Long Do Babies Wear Newborn Clothes?
Well, unless you buy your baby’s entire wardrobe at the same store, there’s a good chance that ALL of their newborn clothes won’t be too small or ALL of their 0-3M won’t be too big at one time.
You’ll find that your baby will have this sort of “current clothes range”. For example, 3 pajamas are getting tight but 2 are the perfect fit and soon they’ll fit into these other ones you have but they still need a few weeks to grow until they can wear the rest.
Does that make sense?
This happens because brands fit and size their clothes differently from other brands. Gerber may fit small, Gymboree may fit big, and Carter’s seems to fit “true to size”. We’ll continue more specific examples of this later, but as you can see, different companies run different fits within the same size/age.
If your baby is right in between two sizes in terms of weight or height, it’s best to size up to ensure a better fit. Your baby will feel more comfortable in items that are a smidge too big rather than anything too tight or short.
If you notice areas where the fabric or elastic is getting too tight on your baby, you need to get the next size ready.
But that moves us to the next question, what’s considered “too small” for your infant?
How to Tell if Baby Clothes are Too Small
If you’re unsure whether your baby’s clothes are getting too small are not, there are some things you can look out for.
- Clothes leave red marks on baby’s skin, possibly around the waistband, wrists (or arms if it’s a short sleeve), or ankles. If any of the elasticated or tapered areas leave red or very indented marks on the skin, it could be a good indication that the item is getting too small. Make sure clothing is never cutting off your baby’s circulation or rubbing their delicate skin.
- The fabric between the snaps is pulled open (or perhaps the snaps won’t snap shut!) or the fabric along the zipper is stretching tight. If the sleeper or jumpsuit is struggling to stay closed, it probably means your little bub needs a bigger size or a more relaxed fit.
- Footed pants or pajamas are getting tight and stretched lengthwise, sometimes even creating a worn out area by the toes. You may notice your little one’s sleepers are a bit tricky to fit up and over the shoulders when the bottom half is already on their legs. This is a telltale sign that it’s time to size up.
- Non-footed pants or pajamas are looking more like capris, ending at the calf. If the bottom is too cropped, your baby has outgrown that pair.
- Onesies are getting difficult to snap shut between the legs. If you need to tug the fabric to get the snaps closed, it’s getting too small for your baby to wear.
- Shirts and other tops are hard to get over the head. Some tops without snaps or envelope necks (the fabric sections that cross over top of each other near the shoulder to give a bigger opening) are a bit tricky to squeeze over babies’ heads. But if it’s really making you (and baby) work to get it on, it may mean that the top is just too small for your infant.
- Shirts rise up the belly. Babies are always wriggling around making shirts tricky to keep down in place, but if the shirt is constantly rising up, exposing their adorable little baby belly, then it’s likely too small for them. If the rest of the top fits comfortably, you could try layering it over top of a onesie so that their skin stays covered and warm, even if the shirt rises up.Otherwise, it’s time to get a bigger shirt.
How to Tell if Baby Clothes are Too Big
It may seem tempting to simply skip a couple sizes so your baby can get more use out of fewer clothes, but that’s usually not a good idea.
As much as I mentioned comfort being the key to baby clothes, well, they shouldn’t be too loose either. In fact, putting them in clothes that are way too big could become a risk to your baby.
We’ll come back to that important piece in the next section, but first, let’s go over how you can tell whether the baby’s clothes are too big.
- Clothes are falling off of your baby. Some clothes may shift a little because, let’s face it, those newborns come out pretty darn tiny! But clothes should not be sliding off the shoulder and down the body or slipping down past the diaper and falling off of your infant. Socks and mittens are about the only items that are ok to be falling off, which they seem to do all too frequently. You can read my rant about that here: Snaps or Zippers for Baby Clothes? 12 Helpful Tips for Dressing Your Newborn
- Sleeves or pant legs are dangling past the hands or feet. If you can’t comfortably fold sleeves or pants to keep them close to your baby’s wrists and ankles, they may be too long for your baby to wear.
- Fabric is gathering together in excessive bunches. A little bunching of the clothing material is normal. Babies contort in all sorts of cuddly positions and their relaxed-fit clothing seems to gather more in certain parts when they do. But they shouldn’t have big clumps of fabric pushing against their tiny bodies and definitely nothing close to their neck or face.
Can I Put My Baby in Clothes That Are Too Big?
Proper fitting articles of clothes are the best and safest option for your baby. One size too big is usually not a problem because baby clothes don’t make big jumps in measurements. However, it is not recommended to put an infant in clothes that are unreasonably larger than their current size.
The reason is that the clothes can actually endanger your infant. Suffocation or strangulation are real risks that can happen with excess material or improper fitting clothes on a baby.
Loose fabric that can cover the baby’s mouth and nose can increase the risk of suffocation, especially at night. This is the main reason that blankets are not recommended in your baby’s crib until AT LEAST 12 months of age (but ideally after 18 months).
Very loose or dangling fabric could also get tangled around the baby and possibly lead to accidental strangulation.
What to Do If Baby Clothes Are Too Big
If your baby clothes are a bit too big or your little one is in between sizes and you want to start putting them in the larger size, there are several things you can do to make the clothes more comfortable.
- Roll sleeves or pant legs. If sleeves or pant legs are just a slightly too long for baby’s limbs, try folding them over once so that they are not covering your infant’s hands or feet.
- Hem the clothes. Some of you may be fairly skillful with the sewing machine and could make minor alterations to your baby’s clothes.
- Fold or cinch a waistband. Certain pants may allow you to fold the waistband so that the pantlegs aren’t so long. You may also be able to cinch it in enough to fit better.
- Put socks over footed pants or pajamas. Once your little one starts moving or crawling, footed pants or pajamas that are too long may get in the way of their movement. Putting a pair of baby socks over top of the footed pants can help keep the bottoms in place so that they’re not getting trapped under your baby as they roam around. Just make sure that the socks aren’t too tight with the extra fabric underneath and that your little mover doesn’t overheat.
Remember that if baby clothes are so large that they could pose a safety risk to your infant, you need to wait for your baby to grow big enough to safely wear them.
What to Do If Baby Clothes Are Too Small
Babies just keep growing so when you notice the clothes no longer fit, it’s time to move them into the next size up. But what do you do with the clothes that are too small? Depending on your situation, there are many options for the clothes that don’t fit your baby anymore.
- Store them for a future sibling. If you think you may want more kids down the road, put the items of clothing into a storage container and into the basem*nt or crawl space or wherever you’d store the items that are not currently in use. Keep it within reach so that in a month or so when your little one has grown out of the next size, you can add them to the bin. Make sure you clearly label the storage bins to not forget its contents!
- Give them to a friend or family member’s baby. Moms often have other mom friends, or family, who are having babies around the same time so if you know of someone with a smaller/younger baby, you could offer the clothes to them when your baby is done. It’s a great way to recycle clothes and save some money for other families you care about.
- Donate them to a charity or shelter. Such a simple gift can have a big impact on those in need. Donate any gently used items to a local charity or shelter that takes infant clothes.
- Sell the clothes online. There are several online local classifieds where you could sell the baby clothes.
- Keep some garments for sentimental value. While it may not be wise to keep all your baby’s clothes for memory’s sake, a few special pieces may be worth saving to look back on.
Which Baby Clothes Brands Run Small?
As I mentioned earlier in the article, some brands seem to run smaller than others. Based on my own experience plus the opinions of many other parents who have used these brands, here are the ones that seem to usually run small:
Gerber
Old Navy
Zara
Burt’s Bees (slim but long)
Which Baby Clothes Brands Run Big?
After diving into many reviews, parents feel that these brands usually run big:
Gymboree
H&M
Gap (depending on the item)
BONDS
Which Baby Clothes Brands Run True-to-Size?
We’ve covered brands that run small and those that run big, but do any actually fit true-to-size? I haven’t personally shopped at all of the stores but, according to experienced parents, the following brands seem to be the most reliable for sizing.
Carter’s
Gap (some items run big)
OshKosh B’gosh
My 1st Years
Primary
Baby Clothes Size Charts from Popular Clothing Brands
Gerber Baby Size Chart
| SIZE | WEIGHT | HEIGHT |
| Preemie | Up to 5 lbs. / Up to 2.3 kg | Up to 17 in. / Up to 43.2 cm |
| Newborn (NB) | 5-8 Ibs. / 2.3-3.6 kg | 17-21 in. / 43.2-53.3 cm |
| 0-3M | 8-12 Ibs. / 3.6-5.4 kg | 21-24 in. / 53.3-61 cm |
| 0-6M | Up to 16 Ibs. / Up to 7.3 kg | 17-26 in. / 43.2-66 cm |
| 3-6M | 12-16 Ibs. / 5.4-7.3 kg | 24-26 in. / 61-66 cm |
| 6-9M | 16-20 Ibs. / 7.3-9.1 kg | 26-28 in. / 66-71.1 cm |
| 12M | 20-24 Ibs. / 9.1-10.9 kg | 28-30 in. / 71.1-76.2 cm |
| 18M | 24-28 Ibs. / 10.9-12.7 kg | 30-32 in. / 76.2-81.3 cm |
| 24M / 2T | 28-32 Ibs. / 12.7-14.5 kg | 32-34 in. / 81.3-86.4 cm |
H&M Baby Size Chart
| SIZE | WEIGHT | HEIGHT |
| <0-1M | <5.5 lb / <2.5 kg | 17 in. |
| 0-1M | 7 lb / 3 kg | 20 in. |
| 1-2M | 11 lb / 5 kg | 22 in. |
| 2-4M | 13 lb / 6 kg | 24 in. |
| 4-6M | 18 lb / 8 kg | 27 in. |
| 6-9M | 20 lb / 9 kg | 29 in. |
| 9-12M | 22 lb / 10 kg | 31 in. |
| 12-18M | 24 lb / 11 kg | 34 in. |
| 1.5-2Y | 27 lb / 13 kg | 36 in. |
Old Navy Baby Size Chart
| SIZE | WEIGHT | HEIGHT |
| Up to 7 lbs | Up to 7 lbs / 3 kg | Up to 18 in. / 46 cm |
| 0-3 mos | 7-12 lbs / 3-6 kg | 19-23 in. / 48-58 cm |
| 3-6 mos | 12-17 lbs / 6-8 kg | 23-27 in. / 58-69 cm |
| 6-9 mos | 17-19 lbs / 8-9 kg | 27-28 in. / 69-71 cm |
| 6-12 mos | 17-22 lbs / 8-10 kg | 27-29 in. / 69-74 cm |
| 12-18 mos | 22-27 lbs / 10-12 kg | 29-31 in. / 74-79 cm |
| 18-24 mos | 27-30 lbs / 12-14 kg | 31-33 in. / 79-84 |
Burt’s Bees Baby Size Chart
| SIZE | WEIGHT | HEIGHT |
| Preemie | up to 6 lbs / up to 2.7 kg | up to 17 in. / up to 43 cm |
| Newborn | 6-9 lbs (9M)/ 2.7-4.1 kg | up to 21.5 in. / up to 55 cm |
| 0-3 months (3M) | 9-12.5 lbs / 4.1 – 5.7 kg | 21.5 – 24 in. / 55 – 61 cm |
| 3-6 months (6M) | 12.5 – 17 lbs / 5.7 – 7.7 kg | 24 – 26.5 in. / 61 – 67 cm |
| 6-9 months (9M) | 17 – 21 lbs / 7.7 – 9.5 kg | up to 28.5 in. / up to 72 cm |
| 12 months | 21 to 25 lbs / 9.5 -11.3 kg | 28.5 to 30.5 in. / 72 to 78 cm |
| 18 months | 25- 28 lbs / 11.3 – 12.7 kg | 30.5 to 32.5 in. / 78 – 83 cm |
| 24 months | 28 – 30 lbs / 12.7 – 13.6 kg | 32.5 to 34 in. / 83 – 86 cm |
Gap Baby Size Chart
| SIZE | WEIGHT | HEIGHT |
| UP TO 7 LBS | up to 7 lbs / up to 3 kg | up to 18 in. / up to 46 cm |
| 0 – 3 mos | 7-12 lbs / 3-5 kg | 18-23 in. / 46-58 cm |
| 3 – 6 mos | 12-17 lbs / 5-8 kg | 23-27 in. / 58-68 cm |
| 6 – 9 mos | 17-20 lbs / 8-9 kg | 27-28 in. / 68-71 cm |
| 6 – 12 mos | 20-22 lbs / 9-10 kg | 28-29 in. / 71-74 cm |
| 12 – 18 mos | 22-27 lbs / 10-12 kg | 29-31 in. / 74-79 cm |
| 18 – 24 mos | 27-30 lbs / 12-14 kg | 31-33 in. / 79-84 cm |
Carter’s Baby Size Chart
| SIZE | WEIGHT | HEIGHT |
| Preemie (P) | Up to 5 lbs / Up to 2.26 kg | Up to 17 in. / Up to 43 cm |
| Newborn (NB) | 5 – 8 lbs / 2.2-3.6 kg | Up to 21.5 in. / Up to 55 cm |
| 3M | 8 – 12.5 lbs / 3.6-5.6 kg | 21.5 – 24 in. / 55-61 cm |
| 6M | 12.5 – 16.5 lbs / 5.6-7.4 kg | 24 – 26.5 in. / 61-67 cm |
| 9M | 16.5 – 20.5 lbs / 7.4-9.2 kg | 26.5 – 28.5 in. / 67-72 cm |
| 12M | 20.5 – 24.5 lbs / 9.2-11.1 kg | 28.5 – 30.5 in. / 72-78 cm |
| 18M | 24.5 – 27.5 lbs / 11.1-12.4 kg | 30.5 – 32.5 in. / 78-83 cm |
| 24M | 27.5 – 30 lbs / 12.4-13.6 kg | 32.5 – 34 in. / 83-86 cm |
As you can see, there’s a fairly wide range when it comes down to sizing baby clothes across different brands. With a bit of understanding of how baby clothes sizes works, you can figure out what to do if baby clothes don’t fit. If they’re too small, you have options of keeping them or passing them on to another family, but you’ll need to get the next size up for your little one. If they’re too big then you can either wait until your infant is ready for that size or alter the garment so that it fits, as long as it’s safe for the baby.
