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How to choose a fitting size of disposable diapers in accordance with the growth of your baby

Size of disposable diapers

Both the tape-type and the pants type have various sizes for every physical development stage of babies.



Pants type


As babies grow, their postures and skeletal structures change. Also, the amount of urine increases and the state of stools changes too. That's why, as the size of our disposable diapers gets bigger, not only do the length and width increase, but the dimensions and shape of the absorber change too. There are many other creative features that take into account babies' growing stages as well as the state of their urine and stools.

How to choose a disposable diaper most suitable for your baby?

There are various types and sizes of disposable diapers.

The reason for that is no other than the fact that babies keep growing and changing.

Also, each baby grows at a different speed and is different in their physical shapes. They are all unique.

Therefore, there are a few points to consider to find the most perfect disposable diaper for your baby.

Now, let’s look at them.

Points to consider while choosing most suitable diapers for your baby

In order to choose the best disposable diaper for your baby that is comfortable and without leakage, check the following points.

1. First, confirm the size

By referring to the weights written on the package, check which applies to your baby.

2. Check which fits the physical shape of your baby

Newborn babies are round and curled up just like when they were in their moms' bellies. As they begin to stand up, their backbones become straighter gradually. The diaper should fit the shape and skeletal structure of your baby at each growth stage, otherwise there would be gaps between the diaper and the body which cause leakage. Let's choose a type that is snug to your baby’s body.

3. When babies are a few months old, check the state of their stools too

4. How is your baby's development in the ability to move?

When is the time to change the size of disposable diapers?

Guideline for changing the size of disposable diapers

Although “Guideline weights” are written on disposable diapers, it is not the only guideline for changing the size.

Guideline for changing to one size bigger

As babies grow, the state of their urine and stools changes too. By observing them carefully, change as necessary to the most suitable size.

Guideline for changing due to features of disposable diaper products

From newborn to nursing period, babies grow rapidly and the state of their stools keep changing too.

Catering to all these changes, moony’s disposable diapers have various features depending on the size.

Newborn → S size

Newborn is for small newborn babies who weigh up to 5kg, as a guideline.


  • When your baby weighs over 5kg
  • When your baby holds his/her head up

S size → M size

moony has achieved a 3-D shaping that fits to babies’ postures and skeletal structures. Newborn and a few months old babies whose size is S are round and C shaped. The structure of these diapers perfectly fits C-shaped bodies creating no gap, which prevents leakage but is not overly tight. “Stretchy fitted gather” that flexibly stretches prevents loose stool from leaking for a few months old babies. As they grow and start to sit down, stand up and walk, their body shapes change too.


  • When your baby weighs over 8kg
  • When your baby starts to sit down and eats baby food (when the number of stools reduces and stools are more solid)


moony (Tape type) → moonyman (Pants type)

As they grow, babies move around more actively.
When babies start to kick their legs up and down, crawl and stand up, and you start to have difficulties in changing diaper, a pants type may be useful. Also, S and M sizes of Moony Natural (pants type) and S size of moonyman Air Fit are equipped with a 3-D “Loose stool pocket” that prevents loose stool from leaking. Moms who have tried them are very happy as stool leakage from the back was reduced greatly.


  • When your baby starts to kick their legs up and down
  • When your baby starts to crawl and stands up
  • When you want to avoid loose stool leakage from the back