What do people get wrong about Japanese clothing size labels?
This answer is a draft. It stays unpublished until legal review and source verification are complete.
"A Japanese M is smaller than a Western S" is a standard complaint from visitors. Japanese shoppers are confused too, because "size 9" (9号), "M" and "38" all appear side by side on the rails. This article explains how the JIS standard works and how to choose by actual measurements instead.
How Japanese size labels work
| Label | What it means | Basis |
|---|---|---|
| S / M / L / LL | Body-measurement ranges set by JIS L4004 and L4005 (e.g. women's M = bust 79–87 cm, height 154–162 cm) | JIS (a voluntary standard) |
| Sizes 7 / 9 / 11 / 13 (7号 / 9号 / 11号 / 13号; women) | JIS numbered sizes. Size 9 = bust 83 cm, waist 64 cm, hips 91 cm, the reference figure (A body type, height 158 cm) | JIS L4005 |
| A / Y / AB / B body (men's suits) | Body type by the difference between chest and waist. A = 12 cm difference (standard), Y = 16 cm (slim), AB = 10 cm, B = 6 cm | JIS L4004 |
| 36 / 38 / 40 (womenswear) | Brand labelling borrowed from the French system. Not JIS | |
| Actual measurements (length, chest width, shoulder width, sleeve length) | The garment measured flat. The most reliable guide | Each maker's own label |
| Legal duty | Under the Household Goods Quality Labelling Act (Japan's labelling law), size is not compulsory (fibre composition, care label and the labeller's name are) | Consumer Affairs Agency |
- JIS classifies body sizes; the garment's actual measurements (ease) are each brand's design. It is normal for a relaxed brand's S and a slim brand's M to measure the same.
- For returns on online purchases, Japan's cooling-off rules do not apply to mail order; return conditions are set by each seller's terms. Buying by actual measurements saves the trouble of returns.
- Conversion charts for visitors are a rough guide only (see the English-language sizing article).
[Verify] Check the JIS range values in JIS L4004/L4005 from the Japanese Standards Association. The point about return terms is based on the Consumer Affairs Agency's mail-order material.
Misunderstanding 1｜M is the same in every brand
M is a body-measurement range; the garment's actual size is decided by the brand. Compare actual measurements (chest width, length).
Misunderstanding 2｜Size 9 is "for small people"
Size 9 is the "standard size", based on the average Japanese woman's figure (bust 83 cm). Size 7 is smaller, size 11 larger.
Misunderstanding 3｜38 is a Japanese size
It is brand labelling borrowed from the French system, and not a JIS standard. Check the brand's own conversion chart.
Misunderstanding 4｜Online purchases can be returned if they do not fit
There is no cooling-off for mail order; returns depend on each seller's terms. Many shops refuse items that have been tried on or had the tags removed. Check actual measurements and return conditions before buying.
Misunderstanding 5｜Size labels are required by law
Under the Household Goods Quality Labelling Act, size is not compulsory (fibre composition, care label and labeller are). Some products carry no size at all. Measure and choose by actual size.
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Sources
- Japanese Industrial Standards Committee (JISC), JIS L4004 "Sizing systems for men's garments" / JIS L4005 "Sizing systems for women's garments" [JIS L4004「成人男子用衣料のサイズ」／JIS L4005「成人女子用衣料のサイズ」]
https://www.jisc.go.jp/
- Consumer Affairs Agency, "Household Goods Quality Labelling Act — Textile Goods Quality Labelling Regulations" (compulsory items) [消費者庁「家庭用品品質表示法 繊維製品品質表示規程」]
https://www.caa.go.jp/policies/policy/representation/household_goods/guide/fiber/
- Consumer Affairs Agency, "Cooling-off and return terms in mail-order sales" [消費者庁「通信販売におけるクーリングオフの適用と返品特約」]
https://www.caa.go.jp/policies/policy/consumer_transaction/
⚠️ Editorial note: the source URLs above were identified by search. Our working environment cannot reach go.jp domains, so the contents have not been checked against the text. Verify every source before publication and record who checked it and when.
About this article
What we share here are ideas and everyday practices passed down among people living in Japan, together with general information drawn from public sources. They are not official recommendations, and they are not professional instruction. Practices vary between households and regions.
This is general information. Results vary from person to person and depend on your own conditions and surroundings.
Please decide for yourself, using your own judgement, whether any of this suits your situation. We cannot accept responsibility for any damage, loss or injury arising from following this article.
Follow the care label and the maker's instructions for any garment, shoe or bag. For expensive or sentimental items, ask a specialist cleaner or repairer.
Sources
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