Japanese Bra Size vs US Size — What’s the Difference?
If you've ever tried to shop for Japanese lingerie and felt confused by the sizing, you're not alone. Japanese bra sizes look completely different from US sizes — and the conversion isn't always obvious. In this guide, we break it down simply so you can shop with confidence.
The Key Difference: Japanese Cups Run One Size Larger
The most important thing to know is this: Japanese cup sizes run one size larger than US cup sizes. So if you normally wear a US 36C, your Japanese equivalent is not a C80 — it's a D80.
This trips up a lot of international shoppers. You see a beautiful Japanese bra in your usual cup size and order it — only to find it's too small. The reason is simple: Japan and the US use different scales for measuring cup size.
How Japanese Band Sizes Work
In the US, band sizes are measured in inches — 32, 34, 36, 38, and so on. In Japan, band sizes are measured in centimetres — 65, 70, 75, 80, 85, 90. The conversion is straightforward:
- JP 65 = US 30
- JP 70 = US 32
- JP 75 = US 34
- JP 80 = US 36
- JP 85 = US 38
- JP 90 = US 40
To convert, simply find your underbust measurement in centimetres and match it to the chart above.
How Japanese Cup Sizes Compare to US Cup Sizes
Here is the full cup size conversion chart:
| JP Cup | US Cup | Bust − Underbust Difference |
|---|---|---|
| A | AA | ~10 cm |
| B | A | ~12.5 cm |
| C | B | ~15 cm |
| D | C | ~17.5 cm |
| E | D | ~20 cm |
| F | DD | ~22.5 cm |
| G | DDD / F | ~25 cm |
| H | DDDD / G | ~27.5 cm |
A Real Example
Let's say you wear a US 34D. Here's how to find your Japanese size:
- Band: US 34 = JP 75
- Cup: US D = JP E
- Your Japanese size: E75
Simple once you know the rule!
Why Does Japan Use a Different System?
Japan developed its own sizing standard based on the metric system, which is more precise than the inch-based US system. Japanese lingerie brands also tend to offer a wider range of sizes — particularly in larger cups — which is one reason Japanese bras are so popular with international shoppers who struggle to find well-fitting lingerie at home.
Tips for Shopping Japanese Bras from Overseas
- Always measure in centimetres — don't guess based on your US size alone
- Use a size calculator — enter your bust and underbust to get your exact JP size instantly
- When between sizes, size up — especially for G and H cup styles
- Contact us if unsure — our team responds within 24 hours with a personal size recommendation
Find Your Japanese Bra Size Instantly
Not sure of your size? Use our free Bra Size Calculator — just enter your bust and underbust measurements and get your size in JP, US, UK, EU and AU instantly.
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