How do “One-Size” cloth diapers fit from birth to potty? Fit Guide and Pros/Cons

The invention of the “one size” diaper has meant a tremendous money saving for families. Rather than buying several sets of diapers in each size needed, most families are able to buy a single “stash” of diapers.  Typically, you only need 24-36 diapers for the duration of your child’s diapering days.  One Size diapers fit babies at their different sizes by having an adjustment, usually on the rise (rise=the front of the diaper), that makes the diaper shorter or taller.  This in combination with a generous waist that closes tighter or looser around the baby with snaps or velcro means the diaper has a long life span. When you first pick up a one size cloth diaper you may be thinking “how will this work from birth to potty training?”  Very good question.

Facts about one size cloth diapers from Dirty Diaper Laundry

Some examples of how the diaper should fit at each stage and age will be very beneficial to parents who are new to cloth diapers. Following the examples and descriptions, there is a list of Pros and Cons on using one size cloth diapers.


Newborn/Infant- Unless your baby is a very heavy wetter, you may get away with just one insert or the “newborn” insert during this phase to cut down on bulk.  Still, fabric between the legs can add to the bulky appearance even if the diapers aren’t stuffed.  At this stage the diaper will fit OVER the belly button even on the smallest rise setting.  This is totally normal.  I made a chart on the one size diapers on a newborn used on my son, 3 years ago, for reference.  Many of the diapers used have new versions by now though.


 Crawlers- Crawling babies present a challenge when it comes to changing the diapers (alligator death roll!) but at this stage babies have often moved to the middle or second to largest rise setting. The diapers will also be fitting under the belly button just a little bit.  The diapers will look less bulky by now.  A baby before crawling is often a little ball of squishy rolls with a nice round tummy.  Right before babies learn to crawl some parents find that the thighs, once too small for the one size diapers, are now getting so large that they just barely fit.  This is when parents also worry their babies are about to outgrow their diapers.  Don’t fret!!!  Crawling babies will start losing that chunk in the legs and around the waist (sad I know) and their thigh size is probably the biggest at this age than it will be for the rest of their diapering days.


Walkers-  Toddlers, walking toddlers, are growing taller!  At this point your “baby” may still be on the middle rise setting or up to the largest.  Some toddlers will be lean and tall, or some may still have a nice healthy layer of baby fat.  Diapers will be at all different settings- you could pair 10 babies born in the same month and they would all wear their one size diapers a bit differently.  Because your toddler is taller, the diaper will start to sit lower, and fit more like underwear on the waist.

one-size-cloth-diapers-fit-walking This will look more and more obvious at they get older. It will look a lot trimmer, unless you are adding extra inserts. This will be the same way the diapers fit until potty learning, though you may need to unsnap the rise later on if you aren’t at this stage just yet. one-size-post-walker-lean

[typography font=”Crafty Girls” size=”24″ size_format=”px”]Pros -vs-Cons:[/typography]

These days most families choose one size diapers, but they aren’t the only option. There are still many brands who make sized diapers.

[typography font=”Crafty Girls” size=”24″ size_format=”px”]Pros:[/typography]

Cost Effective- buying one set of diapers that (in theory) will fit your baby birth to potty training will save you hundreds of dollars. One Size will often cost more than a sized diaper (average OS pocket is $17.95) but because you buy far less you save more.  Compare this to the $1,500 or more spent on disposables and realize that a $500 cloth diaper investment is a smaller price to pay.

Flexible- At times, babies will grow into one size of diaper (or into a larger rise setting) then, when they crawl or walk, go back down a rise snap. There are many ways to customize the fit of your diapers to fit your baby’s stage.

Convenient- It is just so easy to “buy 1 and done” when it comes to one size diapers. No more shopping! (Unless, you really just like buying diapers, but I’ve never heard of such a thing *wink*) Once you have enough diapers, 24 on average but you can get by with less or more, you are set until potty training. Imagine 2+ years of never running to the grocery store for diapers or shopping for another size of diapers when you baby grows. Not bad!  There is a possibility the diapers can wear out over time, see the “cons” section on “wear and tear.”

Good for two in diapers- If you have the fortune/misfortune of diapering two or more babies of different ages at the same time, having a set of one size diapers is very handy.  When you are packing a diaper bag you can pack a bit lighter knowing if either child just needs a change while you are out you can adjust the size as needed.  If one chid’s diapers are low, grab one from your other baby’s basket and readjust the size setting.

[typography font=”Crafty Girls” size=”24″ size_format=”px”]Cons:[/typography]

Fit- It is so rare that a one size diaper will fit a fresh newborn.  The statement “from birth to potty training” is often a bit misleading in that sense.  This does depend on the brand(s) you choose and the build of your child.  It is a safe statement to say that one size diapers fit better starting at 10 pounds, and best the bigger your baby gets.  When parents attempt using one size diapers with a newborn and the fit isn’t perfect, even if it seems to fit, they may experience leaks.  Leaking diapers cause lead to frustrated parents.  Try it, if they don’t fit yet, try again in a week or two.  In the meantime you can look into cheap newborn cloth diaper options.

Bulk- The price you pay for convenience and money savings can often be seen in the bulk department.  Sure, you saved a few hundred bucks, but your baby might look like they have a little junk in the trunk, and in the hood too.  One size pockets can have excess fabric folds even when you use trimmer inserts that lead to a less attractive look.   The snapped down rise also adds some bulk to the front.  If you are using a diaper that has leg elastic sizing, the “scrunched” fabric can also add bulk on the smaller settings.  One size all-in-ones present a unique challenge depending on the way they are made.  All-in-one implies that everything you need is in the diaper, unlike a pocket which lets you choose the size of your insert.  On the smallest settings, you have a lot of extra insert you don’t need that must be dealt with by folding or rolling.  Sized diapers often look trimmer.

Wear and Tear- Using the same diapers over the span or 2+ years can often mean some might need replacing before your child is potty trained.  With one size diapers, it is important to keep that in mind when making purchase decisions.  Research reviews on durability, understand the manufacturer’s warranty and try not to void it, and avoid those “cheap” brands that seem too good to be true.  They may be less expensive, but if you have to replace them 1, 2, or 3 times over for 1 or more children it is still worth it to put your money into pricier, but better made products.  I’ve listed a few of my favorite one size diapers at the end of this post and they are all well made brands.

Appearance- Over the years as one size diapers have become the standard, people seem to have stopped complaining about the extra doo-dads that are present.  Still, when a diaper is on a larger rise setting it means you often see the other snaps.  Some brands will choose a matching color to make it less obvious (yay!) or try to make it “fun” by using a coordinating colored snaps.  Or for cheaper brands they often just use white which means on many colors and prints they stick out like a sore thumb.  And with sizing controlled by leg elastic you get a lot of bunching up that can be less than smooth and attractive.  Sized diapers usually look cleaner.



Now that you are 100% informed on one size diapers you can make a decision on whether they are best for your family.  In my 5+ years of cloth diapering I’ve tried just about all of them.  Here are a few of my favorites: bumGenius Freetime, Moraki Pocket AI2, Gro Via AI2, and Softbums.  All of these brands can be found at one of my favorite retailers, Kelly’s Closet! (affiliate link)


Written By
More from Kim Rosas

10 Oddly Satisfying Things Every Cloth Diapering Parent Secretly Loves

When you deep clean your velcro tabs and the gunk is gone, leaving...
Read More