Nurture Note: Why Japanese Sizes Differ from Australian Ones?

Ever bought the same “M size” in Japan and Australia, only to find one fits perfectly while the other feels tight?

That’s because Japanese nappies like Merries, Pampers, or Unicharm Moony are sized differently – and here’s how to pick the perfect fit. 

1. Japanese Sizing Basics

Japanese nappies are sized mainly by weight (in kilograms) rather than just age.

For example, Japanese Tape nappies:

• NB:Under 5kg
• S:4-8kg
• M:6-11kg
• L:9-14kg

Tip: Japanese sizes often run slightly smaller than Australian brands, so if your baby's weight has passed the middle point of the current weight range, consider going up one size.

2. Signs It’s Time to Size Up:

• Waist or thighs are too tight and leave red marks.
• Tabs are being pulled to the farthest point to close.
• The front panel sits much lower on the tummy.
• More frequent leaks, especially overnight

• Your baby's weight has passed the middle point of the current size range.

Tip: we suggest considering the next size when the baby's weight is at the middle point of the range. For example, size M suits weight range from 6kg to 11kg, so you could go to the next size when a baby reaches 8.5-9kg., and L size suits 9-14kg. (Please note:Size NB is different as it does not have the low range indicator, so you should consider to change to size S when you baby's weight is above 4kg).

3. When to Switch from Tape to Pants:

• Baby is more active, flips over, crawls, or stands.
• Changing tape nappies becomes a wrestling match.
• Pants are easier for quick changes, especially outside.

• Most Japanese Brand Pants start from M size (6 kg+).

4. Choosing the Right Size for Your Baby:

• Don’t rely on age alone – weight and thigh/waist measurements matter.
• If you’re between sizes, try the bigger one first.
•  New brand? Start with a small 1 pack to test the fit.

💡 Need help choosing?

Send us your baby’s weight + thigh measurement, and our team will recommend the best fit for your little one.