Japanese Bra Sizes, Decoded
Cup letter first, centimeters throughout, 2.5 cm cup steps, and every letter one ahead of the Western alphabet. Here is the system, the conversion logic, and a page for all 48 mainstream sizes.
Four rules, one chart
The letter shift is the money fact: a Japanese C70 and a US 32B describe the same body. Everything else: bands in familiar EU centimeters, sisters moving 5 cm at a time: behaves as a European shopper would expect. The converter translates any size both directions; the international guide puts all seven systems side by side.
Japanese sizing: answered
How does Japanese bra sizing work?
Band = underbust in centimeters, labeled in 5 cm steps (65–90 mainstream). Cup = top bust minus underbust, in 2.5 cm steps starting around 10 cm for an A. Notation puts the cup first: C70 means a C cup on a 70 cm band.
Is a Japanese C cup the same as an American C?
No: it's about one letter ahead: a Japanese C corresponds to a US B for the same measurements. The cups start earlier and step slightly wider, so nearest-label conversion shifts every letter down one going JP→US.
What Japanese size am I?
Take your underbust in cm, round to the nearest 5 (that's the band), subtract it from your top bust, and read the difference against 2.5 cm steps from 10 (A). Or use the calculator for your Western size and shift the letter up one: US 32B ≈ JP C70.
Do Japanese bras fit differently beyond the numbers?
As house tendencies, yes: Japanese domestic ranges favor molded, lightly padded cups, softer wires and gentler bands, with mainstream stock concentrated on 65–75 bands and A–E cups. Above that, conversion shopping from full-bust international brands is the practical route.
Opens HauteFlair’s own hub page; use your measured size there. HauteFlair is owned by the same company as Brasize.ai; that relationship never changes the sizing math, charts, or fit advice on this page. How this site makes money.
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Two measurements, no inches added, sister sizes attached.
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