What Diaper Sizes Should I Buy?

Before your little one is born, you’ll no doubt feel the need to stock up on diapers. It’s common to add boxes of them to a registry, as well as receive shower gifts like diaper bags and the ubiquitous diaper cake (basically a “cake” made of several tiers of diapers and tied with ribbon).

The real question is: what sizes should you ask for? And going into more depth with that one, how many of each size do you need to have on hand? After all, the worst possible thing is running out of diapers when you need them the most. Consider this to be your proactive primer on avoiding this situation.

The Basics of Diaper Sizes 

One of the best things about diapers is the fact that they come in standard sizes, just like clothing. While some sizes may change slightly from brand to brand (again, just like clothing), for the most part, they are easy to categorize. This makes it simpler to buy them, because you just need to know the weight of your baby – and this is something that can be estimated at any ultrasound.

Of course, there are always surprises, like the weight being slightly inaccurate or your child arriving premature, but that’s why you purchase some large diapers. Your baby will certainly grow into them.

Preemie Size 

Preemie size diapers are designed for babies that weigh less than six pounds. While they are indeed designed for babies that are premature, sometimes you do get a full-term baby with a low birth weight who needs diapers in this size. With that said, most parents do not need to buy this size, as most newborns fit well into the next size up.

Newborn Size

This is the diaper size that most expecting new parents ask for on registries or receive at showers. That’s because these diapers fit babies that weigh less than ten pounds, making them universal for most newborns (hence the name of the size, of course.) In general, most babies will wear this size diaper for around one month or less, making it crucial to not have a huge stockpile of them.

Size 1 

The size 1 diapers are designed to fit infants who weigh between 8 and 14 pounds. There’s some overlap between them and the newborn size (around two pounds, for the record), meaning that babies who are about to size out of the newborn size but still fit in them can use size 1 diapers. This is the size that babies are in for around three months, depending on their growth stages, so be prepared with a couple of cases of them to begin with.

Size 2 

Next up are size 2 diapers. Designed for babies who are between 12 to 18 pounds, expect your baby to wear this size usually between the ages of 3 and 8 months. That means that for most of their first year, they’ll be in size 2 diapers, using them up at a rate of around 8 or 9 diapers per day. It’s always a good idea to register for diapers in this size as well as size 1 and the newborn option. That way, you’ll be prepared for when your little one officially outgrows the previous size.

Size 3 

When it comes to size 3 diapers, you’ll find that your baby could be in them for quite some time. These diapers fit babies and even toddlers that weigh between 16 to 28 pounds, so you can expect your little one to wear them up to the age of 24 months. Of course, the growth rate of every baby varies quite a bit, but the length of time that the diapers will fit is something to keep in mind. Although you probably won’t ask for diapers in this size on your registry, it’s best to stock up on them before your baby arrives.

Size 4 

A size 4 diaper is for children between the ages of one and a half to three years, who weigh between 22 and 37 pounds. Again, there’s some overlap in weight between this size and the previous one, leaving the main difference as the overall physical size of the diaper. You’ll probably go through between 5 to 7 of these diapers a day, depending on your child and their habits, of course, but you may not want to stock up on them until you determine your little one’s growth rate.

Size 5 

Size 5 diapers are designed to fit children who weigh 27 pounds or more. Although the weight limit is similar to that of the previous sizes, these diapers are considerably larger, as they are meant for kids who are around age 3 or 4. Depending on when you start potty training, you may not go through as many diapers in this size, making it one that you probably should buy as needed, not stock up on.

Size 6 

Size 6 diapers are something that you may or may not need. They fit children who weigh up to 35 pounds and are generally between the ages of 4 and 5. If you manage to potty train your child before this age and weight, then you won’t need size 6 diapers at all, but it might be good to have a few in the pull-up design on hand, just in case of an overnight accident. 

How Many Diapers Does a Baby Go Through Each Day? 

One way to determine the diaper sizes to buy is by considering how many diapers, in general, that a baby will go through over the course of an average day. For example, infants, who have smaller bladders and less control over their bowels, will go through around eight to 12 diapers each day.

As your child gets older, they’ll need fewer diapers, eventually working their way down to between six and nine each day from the ages of five or six months (depending on the child, of course) all the way until they are two. After that, the number will drop considerably until your child is potty trained and using pull-up style diapers through the night, just in case.

What About Girls Versus Boys? 

One of the main questions that people tend to ask is about how many diapers a day a girl will go through versus a boy. This is something that’s very difficult to answer, as many babies of both genders will go through the same number of diapers for the most part. However, since male babies tend to pee when you remove their diaper (it has something to do with the air hitting that part of their anatomy), your boy may go through more diapers simply because you grab a clean one to catch the spray before changing them into a clean one.

How to Stockpile Diapers 

When stocking up on diapers, it’s important to remember that diapers are always a commodity that’s available when you run out of them. It’s not like they are a special item that is hard to find. With that said, many people state that since new parents tend to have more money before their baby is born, it’s always a good idea to stock up on diapers at that time. This way, you have plenty on hand.

Understanding just how many diapers come in a case is the key to stockpiling them properly. In general, you get 140 diapers in a newborn case, 160 in a size 1 case, 140 in a size 2 case, and 130 in a size 3 case. Do the math, assuming that the number of diapers needed per day is fairly accurate, and you’ll have a good idea of how many cases to stock up on before your baby is born.

Stocking Up on Related Supplies 

In addition to stocking up on cases of diapers, there are some related supplies that are great to have on hand. For example, you’ll need diaper cream, as well as wipes. While you could buy several boxes of wipes, keep in mind that they do have an expiration date and, if not stored correctly, could dry out before you use them all. 

Diaper cream, or a natural alternative like coconut oil, is the same way. You may want to buy several tubes or containers, one for each diaper bag and another for your home diaper caddy, but don’t go overboard in this category either.

In Conclusion 

It makes plenty of sense to stock up on diapers before your infant is born. In fact, we encourage it! Understanding the various diaper sizes, as well as the average amount that your baby will go through can make it easier to place them on your registry or just buy cases before your little one arrives. As a parent, it never hurts to be prepared, especially where diapers are concerned, because they are crucial to your baby’s comfort, health, and hygiene.



The Complete Guide to Building a Diaper Stockpile | Mommy: Home Manager

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How Many Diapers Do I Need? A Guide to Stocking Up | Healthline

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The Willow is a modern take on the essential diaper bag! The built in changing station is a life saver. Fashion and function at its best !!! I love my willow

Melissa | Verified Buyer