Shopping Guide
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By onemall 
TL;DR
As of September 2026, Japanese bra sizes are written as a cup letter plus an underbust measurement in centimetres — C70, D75, B80 (some shops print it the other way round, 70C). The number is the same centimetre band that Europe uses, so Japan 65 = US/UK 30, 70 = 32, 75 = 34, 80 = 36, 85 = 38, 90 = 40, and Australia is band-number minus 22 (JP 70 = AU 10). The cup letters are where people get caught: under the Japanese standard JIS L 4006 the cups start at AA for a 7.5 cm difference between bust and underbust and go up in 2.5 cm steps with the letters never doubled — A, B, C, D, E, F, G, H, I[1]. In practice that puts a Japanese cup one letter higher than the US letter for the same body: JP C ≈ US B, JP D ≈ US C, JP E ≈ US D, JP F ≈ US DD, JP G ≈ US DDD/F.
- Quick rule: keep the band number if you already know your EU size; convert inches to the nearest 5 cm if you know your US/UK size; then move the cup up one letter going into Japanese sizing (US 34C → JP D75) and down one coming out (JP E70 → US 32D).
- Japanese bands run smaller at the top end. Mass-market lines from Wacoal, Wing and Triumph Japan usually stop at a 90 or 95 band and an H or I cup; bigger sizes are sold under a 大きいサイズ (large size) label and cost more.
- Measure in centimetres, not letters. A US 32D, a UK 32D and a JP E70 are all roughly a 70 cm underbust with a 20 cm bust difference — if you measure those two numbers you can read the Japanese size straight off the JIS table below and skip the letter arithmetic entirely.
- Nothing here ships abroad by itself. Wacoal, Wing, Triumph, PEACH JOHN, tutuanna and Une nana cool sell through Japan-only web shops and Rakuten stores; the way to get them is a proxy. Prices inside Japan are low — the cards below are ¥2,970–¥3,990 ($20–$28) on the day of writing.
How a Japanese bra size is written
A Japanese label reads like C70: the letter is the cup and the number is the underbust (アンダーバスト) in centimetres, rounded to the nearest 5. Retail listings, especially on Rakuten and Mercari, often flip it to 70C or write it with a space (“C 70”); the meaning is identical. Sets are sold as “B70 & M” — the second size is the matching briefs, in the standard Japanese S/M/L/LL letters.
The system is defined by JIS L 4006, the Japanese Industrial Standard for foundation garment sizing. Bands run in 5 cm increments — 65, 70, 75, 80 and so on — and cups begin at AA for a bust-minus-underbust difference of 7.5 ± 1.25 cm, then increase in 2.5 cm steps, with letters neither doubled nor skipped[1]. So a Japanese “A” is already a 10 cm difference, a “C” is 15 cm, an “E” is 20 cm. There is no DD, no DDD, no FF: the Japanese alphabet of cups simply continues E, F, G, H, I.
Japanese bra band size conversion chart (JP to US, UK, EU, AU, FR, IT)
The band is the easy half, because Japan and continental Europe both use the raw underbust centimetre figure. The US and UK use inches; Australia and New Zealand use dress-size numbers; France and Spain add 15 to the centimetre figure; Italy counts from 1[1].
| Japan (JIS) | US | UK | EU | France / Spain | Australia / NZ | Italy |
|---|---|---|---|---|---|---|
| 60 (underbust 57.5–62.5 cm) | 28 | 28 | 60 | 75 | 6 | 0 |
| 65 (underbust 62.5–67.5 cm) | 30 | 30 | 65 | 80 | 8 | 1 |
| 70 (underbust 67.5–72.5 cm) | 32 | 32 | 70 | 85 | 10 | 2 |
| 75 (underbust 72.5–77.5 cm) | 34 | 34 | 75 | 90 | 12 | 3 |
| 80 (underbust 77.5–82.5 cm) | 36 | 36 | 80 | 95 | 14 | 4 |
| 85 (underbust 82.5–87.5 cm) | 38 | 38 | 85 | 100 | 16 | 5 |
| 90 (underbust 87.5–92.5 cm) | 40 | 40 | 90 | 105 | 18 | 6 |
| 95 (underbust 92.5–97.5 cm) | 42 | 42 | 95 | 110 | 20 | 7 |
| 100 (underbust 97.5–102.5 cm) | 44 | 44 | 100 | 115 | 22 | 8 |
| 105 (underbust 102.5–107.5 cm) | 46 | 46 | 105 | 120 | 24 | 9 |
Two things to notice. First, Japanese and European band numbers are the same number, so “Japanese bra size to European” needs no band conversion at all — only the cup letter shifts. Second, the US/UK band for a Japanese 70 is 32, not 28: the inch band is the underbust in inches rounded up to the next even number, which is why American sizes look bigger than Japanese ones for the same person.
Japanese cup size conversion (JP to US, UK, EU and Australian cups)
The cup is where every “Japanese bra size to US” question actually comes from. Japan measures cups in 2.5 cm steps from a 7.5 cm start[1]; the US and UK use 1 inch (2.54 cm) steps but count from a smaller starting difference and, in the traditional American method, from a padded band size; continental Europe uses 2 cm steps[1]. The result is that a Japanese cup letter sits about one letter above the US letter for the same measurements, and the gap widens slightly at the top because the UK doubles letters (DD, FF, GG) while Japan does not.
| Japanese cup | Bust minus underbust (JIS) | US cup | UK cup | EU cup | Australia cup | France cup |
|---|---|---|---|---|---|---|
| AA | 7.5 cm | AA | AA | AA | AA | AA |
| A | 10 cm | AA–A | AA–A | AA | AA–A | AA–A |
| B | 12.5 cm | A | A | A | A | A |
| C | 15 cm | B | B | B | B | B |
| D | 17.5 cm | C | C | C | C | C |
| E | 20 cm | D | D | D | D | D |
| F | 22.5 cm | DD | DD | E | DD | E |
| G | 25 cm | DDD / F | E | F | E | F |
| H | 27.5 cm | G | F | G | F | G |
| I | 30 cm | H | FF | H | FF | H |
| J | 32.5 cm | I | G | I | G | I |
| K | 35 cm | J | GG | J | GG | J |
Treat this as a good first guess rather than a law: every maker’s pattern is slightly different, and Japanese cups are cut for a shallower, higher bust shape. If you are between sizes, most Wacoal fitters will tell you to go one band down and one cup up (the “sister size”) rather than one band up.
Japanese bra size chart — the sizes you will actually see, converted
Because the two halves shift differently, here is the whole thing done for the common sizes. Read your Japanese size in the left column (or find your home size on the right and read left). This is the table to screenshot before you open a Rakuten or Mercari listing.
| Japanese size | US size | UK size | EU size | Australian size |
|---|---|---|---|---|
| A65 | 30AA–30A | 30AA–30A | 65AA | 8AA–8A |
| B65 | 30A | 30A | 65A | 8A |
| C65 | 30B | 30B | 65B | 8B |
| A70 | 32AA–32A | 32AA–32A | 70AA | 10AA–10A |
| B70 | 32A | 32A | 70A | 10A |
| C70 | 32B | 32B | 70B | 10B |
| D70 | 32C | 32C | 70C | 10C |
| E70 | 32D | 32D | 70D | 10D |
| B75 | 34A | 34A | 75A | 12A |
| C75 | 34B | 34B | 75B | 12B |
| D75 | 34C | 34C | 75C | 12C |
| E75 | 34D | 34D | 75D | 12D |
| F75 | 34DD | 34DD | 75E | 12DD |
| C80 | 36B | 36B | 80B | 14B |
| D80 | 36C | 36C | 80C | 14C |
| E80 | 36D | 36D | 80D | 14D |
| F80 | 36DD | 36DD | 80E | 14DD |
| G80 | 36DDD | 36E | 80F | 14E |
| D85 | 38C | 38C | 85C | 16C |
| E85 | 38D | 38D | 85D | 16D |
| F85 | 38DD | 38DD | 85E | 16DD |
| E90 | 40D | 40D | 90D | 18D |
| F90 | 40DD | 40DD | 90E | 18DD |
Going the other way — American to Japanese bra size — is just the same table read right-to-left: a US 34B is a Japanese C75, a US 36C is a Japanese D80, a US 32DD is a Japanese F70. For UK to Japanese the band is identical to the US and the cup shifts up one Japanese letter until DD, after which UK E = JP G, UK F = JP H, UK FF = JP I. For Australian sizes, subtract 22 from the Japanese band and use the UK-style cup letters.
Japanese vs American bra sizes: the same body, two labels
Put side by side, a Japanese vs US bra size comparison looks like this for one person with a 73 cm underbust and an 88 cm bust: Japan says C75, the USA says 34B, the UK says 34B, Europe says 75B, Australia says 12B, the Philippines (which follows US sizing) says 34B, India (US/UK letters) says 34B, and Korea says 75B. Japan vs Europe is only a cup-letter shift; Japan vs UK and Japan vs USA shift both halves. That is the whole of “Japanese bra sizes compared to US”: same band in different units, cup one letter higher in Japan. Any online Japanese bra size converter is doing exactly this arithmetic — the tables above are the converter, from Japanese to US, US to Japanese, and Japanese to UK, EU or Australian.
Average and biggest sizes. “Average bra size of Japanese women” and “Japanese girls’ average cup size” are asked constantly and the honest answer is a range, not a number: the Japanese market is centred on the 65–75 bands and B–D cups — Wacoal’s own long-running fit surveys, widely reported in Japan, show the average Japanese cup drifting upward over the decades from an A/B norm to today’s C/D — which is why the deepest stock and the lowest prices are at C70, D70 and C75. The biggest cup size in mainstream Japanese lines is an H or I on a 90–95 band; only the dedicated large-size ranges go to J and K, and above that Japanese shoppers buy imported brands. A Japanese “breast cup size chart” is the same JIS table above — Japanese vs Western cup sizing differs only in the 2.5 cm step and the starting point. E65, G70 and similar “small band, deep cup” sizes exist in Japan but are thin on the ground and worth searching second-hand.
How to measure yourself the Japanese way
- Underbust (アンダーバスト). Tape snug and level, directly under the bust, breathing out normally. Round to the nearest 5 cm: 68 cm becomes 70, 73 cm becomes 75. That number is your Japanese band.
- Top bust (トップバスト). Tape level around the fullest point, wearing a non-padded bra or none, standing straight.
- Subtract. Top bust minus underbust, in centimetres. Find the difference in the cup table above: 12.5 cm is a B, 15 cm is a C, 17.5 cm is a D, 20 cm is an E[1]. Halfway between two steps — say 16 cm — is usually fitted as the larger cup in a three-quarter-cup style and the smaller in a full cup.
- Write it Japanese-style: cup letter, then band. 88 cm bust on a 73 cm underbust is a 15 cm difference on a 75 band — C75, which is a US/UK 34B and an EU 75B.
“What’s my Japanese bra size?” is answered by those four steps; every brand’s online size finder (Wacoal’s, Triumph’s) asks for the same two centimetre figures. Japanese lingerie shops do this with a tape in-store for free (a professional fitting is standard at Wacoal counters), and the big brands publish the same method online. The Japanese sizing you get from measuring is more reliable than converting a bra you already own, because the bra you own may itself be the wrong size.
Types of Japanese bra you will see in listings
Beyond the standard wired 3/4-cup, Japanese brands sell a few types that have their own search terms: the minimizer (小さく見せるブラ, “makes it look smaller”), the kimono bra (和装ブラ, a flattening bra worn under a kimono or yukata so the front lies smooth), the nursing bra (マタニティブラ), stick-on and strapless bras (NuBra is a Japanese-market staple), the bralette and bra top, sports and night bras, and one-size / smart-size stretch bras such as Wacoal’s MOOD line, which use S/M/L instead of cups. The Japanese word for bra is burajaa (ブラジャー), shortened to bura; “bra and underwear set” is bura shootsu setto. Sets, plus-size shapewear and bra-and-pants sets are usually cheaper per piece than singles, and a matching set is what most Japanese listings are selling.
Japanese lingerie sizes beyond the bra
Briefs, camisoles and bra tops use the general Japanese apparel letters — S, M, L, LL (XL), 3L, 4L — which are one size smaller than the same letter in the US: a Japanese M is roughly a US S. Our Japanese clothing size conversion guide has the full hip and waist tables for those letters, and the bust ranges used on Japanese tops and dresses. Bra tops and night bras from tutuanna, PEACH JOHN and Uniqlo are sold in those letters rather than in cup sizes, which is why they are the safest thing to buy first if you are unsure of your Japanese cup.
The other two conversions people search alongside this one are Japanese shoe sizes to US and UK (also in centimetres) and Japanese ring sizes to US (a numbered scale of its own).
Japanese bra brands worth knowing, and what size ranges they carry
| Brand | Owner / positioning | Typical size range | Known for |
|---|---|---|---|
| Wacoal | Wacoal Holdings, Kyoto; the reference Japanese lingerie maker[2] | A–I cups, 65–90 bands in core lines; larger in dedicated ranges | Fit research, Salute and Studio Five lines, the Ribbon Bra, the “makes it look smaller” bra |
| Wing | Wacoal’s mid-price brand | A–G, 65–85 | Lesiage and Natural Up Bra basics at ¥2,000–¥4,000 |
| Triumph Japan | Triumph International’s Japanese arm, with Japan-specific product[3] | A–H, 65–90 | Tenshi no Bra (“angel bra”), sloggi ZERO Feel wireless, AMO’S STYLE |
| PEACH JOHN | Wacoal group; young, catalogue-and-web driven | A–G, 65–80 | Push-up and “Nice Body” bras, anime collaborations (Sailor Moon, One Piece) |
| tutuanna | Tutuanna Inc., Osaka; fast-fashion lingerie and socks | A–F, 65–80 | Bra-and-brief sets around ¥2,000, junior bras, night bras |
| Une nana cool | Wacoal group; casual and cotton | A–E, 65–80 | Wireless and cotton bras, cute prints |
| aimerfeel | Value-priced web brand | A–G, 65–85 | The “Raku Bra” wireless line, sets under ¥4,000 |
| Gunze / Atsugi | Hosiery and innerwear majors | Letter sizes (M–LL) more than cup sizes | Cotton wireless bras, seamless and shaping innerwear |
| Uniqlo | Fast Retailing | XS–3XL letter sizes | Wireless bras and bra tops sized by letter, not cup |
Those are the Japanese bra companies that matter for online shopping; a bra is burajaa in Japanese and the lingerie department is ranjerii or inaa (innerwear). A few brands people ask about are not Japanese at all: Bradelis is a New York label with Japanese roots, and the “Japanese” night bras sold on Amazon abroad are mostly Chinese-made imports. The cotton, lace and stitching quality that the search “Japanese bra” is really after lives in Wacoal, Wing, Triumph Japan and the Osaka value brands — all of which ship domestically only.
Japanese bra vocabulary for reading a listing
| Japanese | Reading | Meaning |
|---|---|---|
| ブラジャー | burajaa | bra / brassiere |
| カップ | kappu | cup |
| アンダーバスト | andaa basuto | underbust (the band measurement) |
| トップバスト | toppu basuto | full bust (over the fullest point) |
| アンダー | andaa | band size, e.g. “アンダー75” |
| ノンワイヤー | non-waiyaa | wireless / wire-free |
| ワイヤー入り | waiyaa-iri | underwired |
| フルカップ | furu kappu | full cup |
| 3/4カップ | yonbun-no-san kappu | three-quarter cup (the default Japanese style) |
| ナイトブラ | naito bura | night bra (sleep bra) |
| スポーツブラ | supootsu bura | sports bra |
| ブラトップ | bura toppu | bra top / camisole with built-in cups |
| ショーツ | shootsu | briefs (a set is ブラショーツセット) |
| 大きいサイズ | ookii saizu | plus size / larger sizes (typically E–I cups, 80–100 bands) |
| 小胸 | komune / chiisai mune | small bust (AA–B cup lines) |
Listings also state the cup style (full cup, 3/4 cup, 1/2 cup), the pad type (パッド, removable or fixed) and whether the piece is 新品タグ付き — new with tags. On the used marketplaces the last one matters: a great deal of the Wacoal and Triumph stock on Mercari and Rakuma is unworn stock from closed shops, sold new-with-tags at a third of retail.
How to buy a Japanese bra from abroad
- Convert your size once, in centimetres. Use the measuring steps above, or the quick table. Write down the Japanese form (e.g. D75) and the brand’s brief letter (M or L).
- Search in Japanese. Brand names in katakana plus the size string find far more than English: “ワコール D75”, “トリンプ C70”. Rakuten stores let you filter by cup and band; on Mercari the size is in the title.
- Pick the store type. New retail is on the brands’ official Rakuten shops and Amazon Japan; new-with-tags and discontinued lines are on Mercari, Rakuma and Yahoo Auctions. All of them are Japan-only at checkout.
- Buy through a proxy. Paste the listing into OneMall; we buy it to our Japanese warehouse. For most Japanese shops the service fee is 5% (minimum ¥200, maximum ¥1,000 per order); Mercari purchases are a flat ¥300 per item.
- Consolidate. Lingerie is light: three or four bras and matching briefs still fit the smallest airmail band, so the shipping cost per piece falls fast when you ship them together. See the fee-by-fee cheapest-proxy comparison for how the totals work out, and our best Japan proxy service guide if you are choosing a service.
FAQ
What is a Japanese C cup in US sizes?
Roughly a US B. A Japanese C is a 15 cm bust-to-underbust difference under JIS L 4006[1]; in American sizing that lands on a B cup. Keep the band in centimetres and convert: JP C70 ≈ US 32B, JP C75 ≈ US 34B, JP C80 ≈ US 36B.
What is a Japanese bra size D75 in UK sizing?
34C. The 75 band is a UK 34 and a Japanese D (17.5 cm difference) is one letter above a UK C. The same logic makes a JP E75 a UK 34D and a JP F75 a UK 34DD.
Are Japanese bra sizes smaller than American ones?
The bands are the same body measurement written in centimetres, so they are not smaller — a 70 is a 32 either way. The cups look bigger because the Japanese letter is one step higher than the US letter for the same body. What is genuinely smaller is the range: most Japanese lines stop around a 90 band and an H or I cup.
Japanese bra size conversion to Australia?
Subtract 22 from the Japanese band (70 → 10, 75 → 12, 80 → 14) and drop the cup one letter, using the UK-style letters: JP D75 ≈ AU 12C, JP F80 ≈ AU 14DD, JP G80 ≈ AU 14E.
What does B75 mean on a Japanese bra?
Cup B on a 75 cm underbust band: a 12.5 cm difference between bust and underbust[1], which converts to a US/UK 34A and an EU 75A.
Is a Japanese bra size the same as Korean or Chinese sizing?
Korea and China both use the centimetre band (70, 75, 80) like Japan and the EU, so the number carries over unchanged. Their cup letters follow the international 2 cm-step convention rather than the Japanese 2.5 cm one, so treat them like EU cups in the table above.
What is the average bra size in Japan?
Mainstream Japanese lines are built around B–D cups on 65–75 bands, and Wacoal’s fit surveys reported in Japan describe the average cup as having moved up from A/B decades ago to C/D today; the size you will find most stock of is C70–D70 (a US 32B–32C).
Japanese underwear size to US?
Japanese underwear (briefs, shorts, camisoles) is sized S, M, L, LL, 3L by hip measurement, and a Japanese M is roughly a US S, a Japanese L a US M. The full Japanese underwear size chart with hip ranges is in our clothing size conversion guide.
Where can I find a Japanese bra size calculator?
You do not need one: measure underbust and top bust in centimetres, round the underbust to the nearest 5, subtract, and read the cup off the JIS table above. The conversion tables on this page then give the US, UK, EU and Australian equivalents.
Related reading
- Japanese clothing size conversion — S/M/L/LL, dress numbers and waist sizes
- Japanese shoe size to US and Japanese ring size to US — the other two centimetre-based systems
- Japanese skincare brands — the other half of the Japanese beauty aisle
Last updated: 11 September 2026. Size definitions checked against the JIS L 4006 summary on 11 September 2026; product prices from live Japanese listings the same day. Cup conversions across countries are approximate — brands cut differently.
References
- Bra size — Japanese standard JIS L 4006 (AA = 7.5 ± 1.25 cm, 2.5 cm cup steps, 5 cm band steps) and international band equivalence table (EU cm / US-UK inches / AU-NZ / FR-ES / IT). en.wikipedia.org
- Wacoal Corp. — official size guide and measuring method (Japanese). wacoal.jp
- Triumph International (Japan) — official site and sizing pages (Japanese). jp.triumph.com