Why Japanese Sizes Run Smaller
Japanese clothing sizes run notably small vs US/EU. Japanese L often equals US M. Reason: JIS standard is built around average Japanese body measurements, which differ from Western averages.
The Chart
| Body Dimension | Avg Japanese (1985) | Avg US (1985) | Avg US (2020) |
|---|---|---|---|
| Female height | 158cm | 163cm | 164cm |
| Female bust | 83cm | 91cm | 100cm |
| Female waist | 68cm | 75cm | 87cm |
| Female hip | 91cm | 97cm | 104cm |
| Male height | 170cm | 175cm | 176cm |
| Male chest | 91cm | 100cm | 106cm |
Notes
JIS L 4006 (women's) and L 4001 (men's) were established in 1985 with these baseline measurements. The Japanese standard barely changed; US baseline grew (vanity sizing + actual body changes). Result: an item labeled L in Japan and L in US fit the same body would have been comparable in 1985 but very different in 2025.
FAQs
Are Japanese bodies still smaller?
Average Japanese height + body has grown since 1985 but more slowly than US averages. JIS standards have not been fully updated. So the 'small' impression vs US sizing has actually widened.
Should I always size up for Japanese brands?
Yes, generally 1-2 sizes. US M = JP L. US L = JP LL. Brands selling internationally (Uniqlo US, Muji US) have already converted — those run true to US sizing despite Japanese origin.
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