By Mania, Senior Style Editor at WFashionLady.
My US size is a 34C. In UK brands I have worn a 34C, a 34DD, and a 32D, and one wrong guess about UK cup letters gave me a Panache 34E that was a full cup size too large. I have ordered from Freya, Panache, Marks & Spencer, Boux Avenue, Etam, and Victoria’s Secret, and this guide gives you the band and cup conversions, the sister size rule, and the fit notes from those orders. For clothing and shoes, see our US to UK Size Conversion Chart and US to EU Size Conversion Chart.
Key Takeaways
- US and UK band sizes are the same number. The EU band is the same measurement in centimeters: a US or UK 34 is an EU 75.
- Cup letters A to D match across the US, UK, and EU. After D, the UK runs DD, E, F, FF, while the EU runs E, F, G, H, so a UK DD is an EU E.
- US cup letters after D have no single scale. Victoria’s Secret lists DD, DDD, and G, but other brands differ.
- Subtracting underbust from bust gives about 1 inch of difference per cup letter from A to D. It gave me the right cup in molded T-shirt bras, but not in non-stretch UK bras like Panache, where I needed a DD.
- Sister sizes hold the same cup volume, so a 34C is the same volume as a 32D and a 36B. A 32D in a Freya plunge stopped the band riding up for me, while a 36B in a Victoria’s Secret lounge bra rode up my back.
- From my own orders: my US 34C is a UK 34C and an EU 75C, but in UK brands I have worn a 34C, a 34DD, and a 32D depending on the style.
- My Marks & Spencer band fit snugly on the outermost hook when new and rode up my back after roughly 4 to 6 months of weekly wear and washing, so I check which hook I am on, not only the size on the tag.
Bra Band Size Chart: US, UK, EU and FR
| US / UK Band | EU Band (cm) | FR Band |
|---|---|---|
| 28 | 60 | 75 |
| 30 | 65 | 80 |
| 32 | 70 | 85 |
| 34 | 75 | 90 |
| 36 | 80 | 95 |
| 38 | 85 | 100 |
| 40 | 90 | 105 |
| 42 | 95 | 110 |
| 44 | 100 | 115 |
The French band is the EU band plus 15. The cup letter stays the same when you convert the band, so a US 34C becomes an EU 75C. French sites list the same band as 90.
When I browsed European boutique lingerie on Zalando’s European site, a US 34 band was listed as 75, which matches this chart. I only checked sizing there against the product page guides and did not order from those listings.
Bra Cup Size Chart: UK vs EU
| UK Cup | EU Cup |
|---|---|
| A | A |
| B | B |
| C | C |
| D | D |
| DD | E |
| E | F |
| F | G |
| FF | H |
Past H, some brands skip letters, so use the brand’s own chart for larger cups. The UK scale has no double E: it goes E, F, FF, G, GG.
What About US Cup Sizes?
The US has no single cup scale after D. Victoria’s Secret, for example, lists DD, DDD, and G after D (with a second letter printed in brackets beside DD and DDD), while other brands use different letters or stop at different points. On a scale like that, DD is the first cup after D, exactly as it is in the UK, so a US DD sits at the same step as a UK DD, and a UK E is one step larger. For a US brand, use that brand’s own chart rather than a general conversion. For a UK or EU brand, the table above applies.
How to Read a Bra Size and Sister Sizes
I use a sister size when the band feels wrong but the cup volume is right. When the band goes down one size, the cup goes up one letter, and when the band goes up one size, the cup goes down one letter, so both sizes hold the same cup volume. The cup letter is relative to the band, so the same letter holds more volume on a bigger band. I have tried three moves. Going down one band size helped only partly (34C to 32D in a Freya plunge stopped the band riding up, but the wire still floated slightly). Going down two band sizes was mixed: in a 30DD Freya wireless, unlined micro-mesh bralette, the 30 band held firmly with no underwire to poke into my underarm, but the shorter band pulled the side seams too far forward toward the center. Going up did not work (34C to 36B in a Victoria’s Secret lounge bra, where the band rode up and the straps dug in).
| Your Size | Sister Size (Band Down) | Sister Size (Band Up) |
|---|---|---|
| 34B | 32C | 36A |
| 34C | 32D | 36B |
| 36C | 34D | 38B |
How I Measure Before I Order
Band: I measure directly beneath the bust line, after exhaling fully, with a soft measuring tape held snug and level around my ribcage.
Bust: I measure over the fullest part of the bust while wearing an unlined, non-padded bra, with the tape lying loosely and flat across the nipples so it does not press into the tissue.
I then check those two measurements against the brand’s own size chart, since brands convert them differently.
From Your Measurements to a Bra Size
Subtract your underbust measurement from your bust measurement. Each inch of difference is roughly one cup size, and from A to D the letters are the same in the US, UK, and EU.
| Bust Minus Underbust | Cup |
|---|---|
| 1 inch | A |
| 2 inches | B |
| 3 inches | C |
| 4 inches | D |
Treat the tape numbers as a starting point, not a final answer: bands are cut differently from brand to brand, and the same body ended up in a 34 band in some of my bras and a 32 band in others, so check the brand’s own chart for the band as well. For cups past D, the letters differ by system, so use the tables above and the brand’s own chart.
I use the bust and underbust difference as my baseline before trying a bra on. It matched my fit in molded T-shirt bras, but only partially overall: in non-stretch unlined UK bras like the Panache I needed a DD whatever the inch difference said.
My Fitting Notes From UK and European Brands
My US size is a 34C. That is a UK 34C and an EU 75C, because the US and UK scales are identical up to D and a US band of 34 is an EU band of 75. In practice, the construction of the bra decided my size more than the tag did. These notes come from my own orders from Freya, Panache, Marks & Spencer, Boux Avenue, Etam, and Victoria’s Secret.
| Brand and Style | Size I Ended Up Wearing | What Happened |
|---|---|---|
| Panache, unlined non-stretch balconette | 34DD | I ordered a 34E, assuming a UK E was the same as a US DD. A UK E is one step larger than a DD, so it was a full cup size too large, with wrinkled fabric and a gap at the top of the cup. The 34DD sat flush against my sternum with no wrinkling at the top. |
| Freya, unlined plunge | Tried 34C, then 32D | The center wire of the 34C floated on top of the inner breast tissue. The 32D tightened the band and stopped it riding up, but the wire still floated slightly. |
| Freya, unlined balconette with a higher gore | 34C | The taller center bridge kept the wire flat against my sternum, and the 34 band was comfortable all day without digging into my ribcage. This is the Freya I kept. |
| Marks & Spencer, molded T-shirt bra | 34C | It fit snugly on the outermost hook when new. After roughly 4 to 6 months of weekly wear and machine washing, even on gentle cycles, the band rode up my back. |
| Boux Avenue, satin plunge push-up | 34C | The band was uncomfortably tight at first, so I used a 2-hook bra extender for the first 6 to 8 washes. After about two months it had softened and I wore it on the outer hook without the extender. The cups still gap at the top when I sit or lean forward, because the stiff molded foam holds its shape instead of moving with me. A 34B overflowed the cup, so 34C is the right volume, and I now keep this bra for standing and evening outfits rather than everyday wear. |
| Victoria’s Secret, wireless lounge bra | Tried a 36B | I went up a band for a looser feel at home. The band lacked anchor tension and rode up my back, and the straps dug in within two hours of wear. |
| Etam, lace plunge | Ordered a 75E | The tag and product page read 75E, and Etam’s size guide listed it against a UK/US DD to E range. By the chart in this guide, a 75E is a UK 34DD, the same size I wear in Panache, yet the cups were too deep, with a visible gap and wrinkling across the apex of the lace. |
Why My Size Changed by Style
This is my own explanation from these orders, not a rule. In smooth molded T-shirt bras, the pre-formed foam cup holds its own shape, so my 34C worked. In rigid, unlined UK balconette styles like the Panache, the fabric has no stretch, and I needed the extra cup depth of a 34DD to stop the wire digging in at the sides. In Freya, the cut mattered more than the size: the plunge needed a 32D to stop the band riding up but its low center wire still floated, while the higher-gore balconette in my own 34C kept the wire flat. The one exception was the Boux Avenue push-up: 34C was the right volume there, but the stiff molded foam still gapped when I leaned forward, which is a matter of shape, not size.
Fit Problems I Have Seen in My Own Bras
| Sign | Where I Saw It |
|---|---|
| Band riding up the back | M&S T-shirt bra after months of wear, and the Victoria’s Secret 36B |
| Cups gapping at the top when I sit or lean forward | Boux Avenue satin plunge push-up in 34C, where the stiff molded foam holds a rigid shape |
| Cups too deep, with a gap and wrinkling across the apex | Etam lace plunge in 75E, and the Panache 34E |
| Underwire floating on top of the inner breast tissue instead of sitting flat against the sternum | A Freya unlined plunge in 34C. The center wire of a plunge is cut low, and in this shallow cup it rested on the tissue. The 32D plunge fixed the band but the wire still floated slightly. A Freya unlined balconette with a higher gore in 34C kept the wire flat against my sternum. |
| Straps digging in | The Victoria’s Secret 36B, where the loose band pushed the weight of the bust onto my shoulders |
Three Habits That Save Returns
Convert the band with the chart, but check the cup letters against the brand. My 34E mistake came from assuming a UK E equals a US DD. Even a correct conversion can run deep: a 75E from Etam, which is the same as my Panache 34DD on this chart, had cups that were too deep.
Try the sister size when the band feels soft. A 32D in a Freya plunge stopped the band riding up, though the floating wire needed a different cut, the higher-gore balconette.
Give a firm UK band time before you judge it. My Boux Avenue band was uncomfortably tight at first. A 2-hook extender got me through the first 6 to 8 washes, and after about two months I wore it on the outer hook without the extender.
Frequently Asked Questions
What is a 34C bra size in EU sizes?
My US 34C is a UK 34C and an EU 75C. The band converts from 34 to 75, and the C cup stays the same.
What is a UK DD bra size in EU sizes?
A UK DD is an EU E. The UK scale runs D, DD, E, F, FF, while the EU scale runs D, E, F, G, H. This is the step I got wrong with Panache: I ordered a UK E when a DD was the size I needed.
What is a sister size in bras?
A sister size has the same cup volume on a different band: go down one band size and up one cup letter, or up one band size and down one cup letter. My 34C has the sister sizes 32D and 36B. In my own orders the 32D stopped band ride-up in a Freya plunge and the 36B did not work in a Victoria’s Secret lounge bra.
Final Thought
The tables get you close, but how the bra actually sits settles it. My 34C became a 34DD in a rigid UK balconette, and in Freya the higher-gore balconette in my own 34C fixed what a 32D plunge could not. The tag alone would not have told me that.
Sources
Bra sizing systems, band conversion, and cup sequences: Bratabase, Bra sizing systems and r/ABraThatFits, Sizing Systems. US cup letters: Victoria’s Secret, Size & Fit: Bras & Bralettes. Measurement to cup size: Tutti Rouge, difference between bra cup sizes. Sister sizes: ThirdLove, Bra Sister Sizes.
