Japanese Diaper Sizes Explained: Merries Newborn, S, M, L & Pants Guide
Our site may contain affiliate links.
Japan / Baby & Kids / Baby Care
Japanese Diaper Sizes Explained: Merries Newborn, S, M, L & Pants Guide
Japanese diaper sizes make more sense when you compare weight + tape/pants format together.
Kao's current Merries Japan lineup gives clear weight ranges for tape and pants diapers.
Merries Japan: current size map
Merries tape diapers currently include newborn sizes, S and M. Pants extend from S through M, L, Big and larger sizes. The same letter can have a different weight range in tape vs pants.
Current Merries pants S guideline.
Current Merries pants M guideline.
Current Merries pants L guideline.
Do not buy Japanese diapers by the letter alone. Check baby weight + tape or pants + current brand chart.
Current Merries Japan size examples
| Type | Size | Current weight guide |
|---|---|---|
| Tape | Newborn | birth–3kg / birth–5kg variants |
| Tape | S | 4–8kg |
| Tape | M | 6–11kg |
| Pants | S | 4–8kg |
| Pants | M | 6–12kg |
| Pants | L | 9–14kg |
| Pants | Big | 12–22kg |
Why M can mean two slightly different things
Merries' current tape M is 6–11kg, while pants M is 6–12kg. This is exactly why an overseas buyer should not assume “M is M.”
What to check before importing a case
Use the current manufacturer range as your first filter.
The fit range can differ.
Japan package counts can change by line and size.
Diapers are light but extremely bulky.
Babies grow unpredictably, and fit depends on body shape as well as weight.
Official source
Kao Merries — current product lineup
Official Merries Japan size chart
Bottom line
For Japanese diapers, the safe shopping order is weight → format → size → pack count. The letter alone is not enough.
