Sized vs One Size Cloth Diapers: Why You May Want to Consider Both!

By April Duffy •  Updated: 05/24/24 •  8 min read

When I first started cloth diapering seven years ago sized diapers were more popular and available than today because one-size diapers were somewhat new, but the one-size diapers were all the rage.

Following the trend, I chose all one-size diapers systems, and really, I think that was a wise decision for me, with my one child who potty trained late-ish and didn’t go to daycare, but that may not be the case for everyone.

If you’re considering a sized diaper system, keep reading because your gut may be leading you in the right direction and I’m going to tell you all the pros and cons of sized and one-sized diapers; but first, let’s make sure we are using the same cloth diaper lingo.

What are One-Size Cloth Diapers?

Illustration of a One-Size Cloth Diaper on babies of different ages.

One-size diapers are just that, a one-size-fits-all diaper that aims to be so adjustable that it can fit any baby from the newborn stage to potty training. These diapers can have snap or Velcro “wings” that make the waist smaller or larger, and will also have snaps along the center of the diaper to make the “rise” shorter or longer to accommodate different heights.

Will One-Size Cloth Diapers Fit Newborns?

Now does a one-size system really fit a baby from birth to potty training? Not usually. It depends on how big or small your newborn is. Most one-size diapers claim to fit babies from about 6 or 7 lbs to 35 lbs. Often these diapers fit best from about 8lbs on.

According to Medical News Today, “The average weight of a baby born at 37–40 weeks ranges from 5 lb 8 oz to 8 lb 13 oz.”

Since most one-size diapers fit best from about 8lbs on, you can expect a good many babies won’t fit them at birth.

If you have a 9 lb baby, you’ll be fine, but that’s more of an exception than the rule.

When Do One-Size Cloth Diapers Fit?

In my experience, one-size diapers fit most babies well around two or three months old. Of course, in the case of twins, multiples, or premies, it can be even longer before they reach that 8lb mark.

Once they do fit, can a one-size last your child up until potty training? Yes. Most one-size diapers fit up to about 35lbs. While your 9-month-old, delightfully-rolly baby may be 25lbs or more, you don’t have to panic; most kids won’t reach that 35lb mark until they are much older. This is because as babies grow their weight gain slows and they stretch out, growing taller.

With the exception of any developmental delays that delay potty training, most babies will potty train before they reach the weight limit of those one-size diapers.

What are Sized Diaper Systems?

Sized diapers are diapers that come in several sizes, of which you’ll need a few to diaper your baby from birth to potty learning, just like disposable diapers. The sizes may be small, medium, large, or size 1, size 2, etc.

The most common sized diaper systems you’ll find are prefold cloth diapers and fitted cloth diapers. Both of these cloth diaper types need to be used with a cloth diaper cover, and many times parents will choose a cloth diaper cover that’s one-size — although Thirsties Duo Wraps and diaper covers are great cloth diaper cover options that are sized.

Sized diapers with the pul built-in — like all-in-ones, all-in-twos, and pocket diapers — will still have snaps or Velcro at the top to make the diaper fit well around the waist, like disposables. These diapers often won’t have any adjustability in the rise, however. This isn’t a hard-and-fast rule however as Thirsties Duo Wraps, which are sized diaper covers, do have rise snaps.

If you compare different sizes in a sized diaper system, you’ll see each size is bigger, just like your baby’s clothing.

Thirsties sized duo wraps.

Pros and Cons of One-Size Cloth Diapers

One-Size Cloth Diaper Pros

One-Size Cloth Diaper Cons

Pros and Cons of Sized Cloth diapers

Sized Cloth Diaper Pros

Sized Cloth Diaper Cons

Conclusion: Are One-Size or Sized Diapers for You?

All in all, whether you choose to do with the standard one-size diapers, or a sized system will come down to two things:

  1. What Type of Cloth Diapers You’re Going With: Again, prefolds and most daytime fitted diapers (like Green Mountain Diapers‘ workhorse diapers) come in sized options, but very few pocket diapers for example are sized.
  2. If You’re Going to Cloth Diaper More Than One Child. Sized diapers make sense if you’re planning on using them for multiple children as they will last longer, but one-sized diapers are less expensive if you’re just using them on one child.

If you need more help choosing the right cloth diapers for you, click here.

April Duffy

April is the founder of Cloth Diapers for Beginners and author of The Cloth Diaper Wash & Care Handbook. Since 2015, April has helped well over 75,000 parents and caregivers cloth diaper their children through this website, her book, her YouTube Channel, and the Cloth Diapers for Beginners Facebook Group.