Bra Size Calculator
EU 75C is 34C in US and UK sizing, 90C in France and C75 in Japan. From a measurement instead, an underbust of 30 in and a bust of 36 in is 30DDD/F US and 30E UK (34B with the older add-4 method), so sizes vary by brand and method.
How to use
- To convert a size you already know, choose "Convert a size label", type it (75C, 34B, 85D or C75) and leave the system on auto-detect, or pick EU, US, UK, FR, AU or JP yourself.
- To find a size from scratch, measure snugly around your ribcage directly under the bust, with the tape level, after breathing out. This is the underbust.
- Measure around the fullest part of the bust, with the tape level and not tight. This is the bust.
- Enter both in inches or centimeters. Choose the band method: the first rounds the underbust to an even number; the second is the older method that adds 4 or 5 inches.
- Read your size in each system and your sister sizes, then try the bra on. Fit differs by brand, so use the result as a starting point.
How it works
Converting a size label uses the common brand label chart, not your body. US and UK bands are the same number, Australia and New Zealand subtract 22 (US 34 = AU 12), the EU band is 60 + 2.5 x (US band - 28), so US 28 = EU 60, US 30 = EU 65, US 32 = EU 70 and US 34 = EU 75, France adds 15 to the EU band, and Japan uses the EU band with the cup written first (C75). Cup letters are matched position by position: US DD/E = UK DD = EU E. Auto-detect treats a letter-first label as Japanese, a band of 60 or more as EU, and anything smaller as US.
There is no single industry standard for bra sizes. Brands and countries use different rules, so the same measurements can give different sizes. This tool fixes one set of rules, shown below, and applies it the same way every time.
Band (US and UK): with the default method the underbust in inches is rounded to the nearest even number, and 29 rounds up to 30. With the older method the underbust is rounded to a whole number and 4 is added if it is even or 5 if it is odd. UK bands are the same numbers as US bands.
Cup: bust minus band, rounded to the nearest inch, one cup letter per inch. A difference under 1 is AA, then A, B, C, D and so on. US letters run DD (also called E), DDD (F), DDDD (G), H. UK letters run DD, E, F, FF, G, GG, H, HH, J.
US, UK and Australian sizes follow the inch measuring custom above. Australian and New Zealand band = US band - 22, so US 34 is AU 12. Australian cups follow UK letters up to DD, then single letters.
EU, French and Japanese sizes are worked out directly from your body in centimeters, so they can differ from the label conversion tables brands print (such as US 30 = EU 65). In-store labels also vary by brand. Inch entries are converted to centimeters first.
EU uses the European standard EN 13402: band = underbust rounded to the nearest 5 cm, and one cup for every 2 cm of difference between bust and underbust, with 10 to 12 cm as AA, 12 to 14 cm as A and so on. French band = EU band + 15, with the same cup. Outside that range the tool shows a dash.
Japan is not converted. It is worked out directly in centimeters with the Japanese standard JIS L 4006: band = underbust rounded to the nearest 5 cm, and cup from the difference between bust and underbust, with AA at 7.5 cm and one letter every 2.5 cm (A 10 cm, B 12.5 cm, C 15 cm, each plus or minus 1.25 cm). Japanese labels put the cup first, as in C75. Outside that range the tool shows a dash.
Cup letters by difference in inches
| Bust minus band | US | UK | AU, NZ |
|---|---|---|---|
| under 1 | AA | AA | AA |
| 1 | A | A | A |
| 2 | B | B | B |
| 3 | C | C | C |
| 4 | D | D | D |
| 5 | DD / E | DD | DD |
| 6 | DDD / F | E | E |
| 7 | DDDD / G | F | F |
| 8 | H | FF | G |
| 9 | I | G | H |
Bra size conversion chart
| US / UK band | EU band | French band | AU / NZ band | Japan band |
|---|---|---|---|---|
| 28 | 60 | 75 | 6 | 60 |
| 30 | 65 | 80 | 8 | 65 |
| 32 | 70 | 85 | 10 | 70 |
| 34 | 75 | 90 | 12 | 75 |
| 36 | 80 | 95 | 14 | 80 |
| 38 | 85 | 100 | 16 | 85 |
| 40 | 90 | 105 | 18 | 90 |
Cup letters in each system
| US | UK | EU / France | AU / NZ | Japan |
|---|---|---|---|---|
| AA | AA | AA | AA | AA |
| A | A | A | A | A |
| B | B | B | B | B |
| C | C | C | C | C |
| D | D | D | D | D |
| DD/E | DD | E | DD | E |
| DDD/F | E | F | E | F |
| DDDD/G | F | G | F | G |
| H | FF | H | G | H |
| I | G | I | H | I |
Band conversion
| US / UK | Australia / NZ |
|---|---|
| 28 | 6 |
| 30 | 8 |
| 32 | 10 |
| 34 | 12 |
| 36 | 14 |
| 38 | 16 |
| 40 | 18 |
EU and French sizes (EN 13402)
| Underbust | EU band | French band | Bust minus underbust | Cup |
|---|---|---|---|---|
| 63 to 67 cm | 65 | 80 | 10 to 12 cm | AA |
| 68 to 72 cm | 70 | 85 | 12 to 14 cm | A |
| 73 to 77 cm | 75 | 90 | 14 to 16 cm | B |
| 78 to 82 cm | 80 | 95 | 16 to 18 cm | C |
| 83 to 87 cm | 85 | 100 | 18 to 20 cm | D |
| 88 to 92 cm | 90 | 105 | 20 to 22 cm | E |
Japanese cups (JIS L 4006)
| Bust minus underbust | Cup |
|---|---|
| 7.5 cm | AA |
| 10 cm | A |
| 12.5 cm | B |
| 15 cm | C |
| 17.5 cm | D |
| 20 cm | E |
| 22.5 cm | F |
| 25 cm | G |
Sources and limits
- The US and UK band and cup rules follow the Wikipedia article Bra size, which describes the underbust-plus-0 and underbust-plus-4 methods and the one-cup-per-inch rule. The Australian band conversion is the one in that article. Brand label charts (Freya, Panache) map US 30 to EU 65; this tool does not use that mapping for EU and France because it works those out from centimeters.
- Cup letters differ between countries above D, and brands do not all agree. US labels vary most: some brands use DD, DDD, G, H and others DD/E, DDD/F. This tool uses the most common pairing, where UK E = US DDD and UK FF = US H.
- The EU and French sizes follow EN 13402 (5 cm bands, 2 cm cups from AA at 10 to 12 cm). The Japanese rule follows JIS L 4006 (5 cm bands, cups from AA at 7.5 cm in 2.5 cm steps). The standards themselves are sold by standards bodies; the values here come from published summaries of them.
- Wikipedia and the American National Standards Institute both note that bra sizing is not standardized and varies between manufacturers. Brand charts take priority over this tool.
- Measurements are for adults. Pregnancy, weight change, breast surgery and bra style all affect fit, and a professional fitting can help.
FAQ
Why do different calculators give me different sizes?
Because bra sizing is not standardized. Some use underbust plus 4 inches for the band, some use the underbust itself, and cup letters are not the same from brand to brand. This tool works out EU, French and Japanese sizes from your body in centimeters and US, UK and Australian sizes from the inch custom, so they may not match the label conversion chart a brand prints. Treat any result as a starting point and try the bra on.
Can I use this as a bra size converter between US, UK, EU, FR and JP?
Yes, from your measurements. Enter your underbust and bust once and the tool shows the matching size in US, UK, EU, French, Australian and Japanese sizing side by side. You can also type an existing label such as 75C, 34B or C75 and convert it directly with the label chart described above. Brands differ from the chart, so measuring yourself is the more reliable route.
What is 75C in US bra size?
EU 75C is 34C in the US and UK, 12C in Australia and New Zealand, 90C in France and C75 in Japan. The EU band 75 corresponds to US 34, and the cup letter C stays in the same position.
What is the 32DDD bra size equivalent?
US 32DDD is 32E in UK sizing, 70F in EU sizing, 85F in France, 10E in Australia and New Zealand, and F70 in Japan. The cup letters DDD and F are the same cup in US labels, so 32DDD is also written 32F. Sister sizes are listed in the converter.
What does C75 mean on a bra label?
It is the Japanese way of writing the size, with the cup letter first. C75 is the same as EU 75C and US 34C. Type it into the label converter and the system is detected automatically.
What are sister sizes?
Sizes with about the same cup volume on a different band. Go down a band and up a cup, or up a band and down a cup: 30E has the sister sizes 28F and 32DD. They help when a bra fits in the cup but the band is too loose or too tight.
Which method should I choose?
The default (band equals your underbust rounded to even) matches what many fitting guides and stores now use. The older add-4 method gives a larger band and a smaller cup for the same measurements. If one fits better in the shop, use that one.
How should the band feel?
Firm and level. You should fit two fingers under the band, and most of the support comes from the band, not the straps.
Is my data sent anywhere?
No. The calculation runs in your browser and nothing you type leaves your device.