UK vs US bra sizes: why is D the same but G is not?
UK and US cup letters are identical from A through D. Above D the UK ladder inserts doubled letters that the US ladder does not use, so every step higher pushes the two systems further apart. A US G is a UK F, and a UK G is a US I. The UK names 15 cup steps where the US names 10. Band numbers are the same in both countries, so only the letter changes. Check which system a brand uses before you convert.
That is not a rounding error. Below D the two systems name the same volume with the same letter. Above D they separate, and by G they describe two different cups entirely. This guide gives you the whole ladder, in both directions, and tells you which of our brands sits on which system.
- A, B, C and D are identical in both systems. A 34C is a 34C in London and in New York. No conversion is needed at or below D.
- The UK ladder adds doubled letters. DD, FF, GG, HH and JJ are extra named steps that the US ladder skips, and they are the entire cause of the drift.
- A US G is a UK F. A UK G is a US I. Two full cup volumes separate the same letter in the two systems.
- Band numbers are the same in the UK and the US. A 34 band is a 34 band. European, French, Australian and Japanese bands use different numbers entirely.
- The UK names 15 cup steps; the US names 10. That is why British houses dominate above a G and why our deepest cups come from Panache, Cleo and Sculptresse.
- Our own DDD and E collections describe the same cup. We carry 16 styles under DDD and 39 under E because vendors label the same volume two ways.
Why the UK and the US count cups differently
The UK and the US measure cup volume the same way and then name the results differently. Both systems define one cup size as roughly one inch of difference between the bust measurement and the underbust measurement. One inch over the band is an A, two inches is a B, three is a C, four is a D. Up to that point the two countries agree completely.
The split is in the naming above D. The UK ladder continues by alternating single and doubled letters, so the fifth step is DD, the sixth is E, the seventh is F, the eighth is FF. The US ladder uses DD for the fifth step and DDD for the sixth, then abandons the doubling and jumps straight to G, H, I and J. Because the US skipped E and F as standalone letters, every letter from G upward sits two steps lower on the American ladder than the same letter does on the British one.
Both systems step in roughly one inch of bust-to-underbust difference. Nothing about the physical cup changes at the border. Only the letter printed on the tag changes.
Fifteen named UK cups run A to K without a gap. The US names ten and leaves the space between DDD and G unlabelled, which is where the two ladders come apart.
A system with more named steps can grade wires, cup depth and strap placement in smaller jumps. That is why the specialist full bust houses are British and why they run so far up the alphabet.
No standards body enforces cup letters. Individual brands publish their own charts, and a few US labels use UK letters. The brand chart always outranks the general rule.
The full UK to US cup conversion, step by step
The table below is the complete conversion, counted by volume step rather than by letter. Step 1 is one inch of difference over the band, step 2 is two inches, and so on. Reading across a row gives you the same cup named in three systems. The rows marked identical are the ones where no conversion is needed at all.
| Step over band | UK cup | US cup | EU / JP cup | Same letter? |
|---|---|---|---|---|
| 1 | A | A | A | Identical |
| 2 | B | B | B | Identical |
| 3 | C | C | C | Identical |
| 4 | D | D | D | Identical |
| 5 | DD | DD (sometimes written E) | E | Last agreement |
| 6 | E | DDD (sometimes written F) | F | Diverged |
| 7 | F | G | G | Diverged |
| 8 | FF | H | H | Diverged |
| 9 | G | I | I | Diverged |
| 10 | GG | J | J | Diverged |
| 11 | H | No standard letter | No standard letter | UK only |
| 12 | HH | No standard letter | No standard letter | UK only |
| 13 | J | No standard letter | No standard letter | UK only |
| 14 | JJ | No standard letter | No standard letter | UK only |
| 15 | K | No standard letter | No standard letter | UK only |
Two details in that table are worth reading twice. The first is that the US and continental European ladders are the same ladder above D, with DD and DDD standing in for E and F. The second is that the letter E means step 5 in the US and in Europe but step 6 in the UK, which is the exact point where careful shoppers start going wrong.
Why a UK G is not a US G
A UK G is two full cup sizes larger than a US G. On the volume ladder a US G sits at step 7 and a UK G sits at step 9. Translated into measurements, a US 34G is about seven inches of bust-to-underbust difference and a UK 34G is about nine. That is roughly two inches of extra cup depth on the same band.
The same gap runs in reverse. A US G converts to a UK F, and a UK F is what most American G-cup wearers should be reaching for when they try Panache or Cleo for the first time. Buying a UK G because the US label said G is not a small mistake. It is the same order of error as buying a size 10 shoe when you need an 8.
Wearing a US G and ordering a UK G. The result is a cup that gapes along the upper edge, a wire that sits too wide at the underarm, and straps tightened hard to stop the whole thing sliding. The fit reads as a strap problem. It is a cup volume problem, and the fix is to drop to a UK F.
The mirror-image error is just as common and harder to spot. A UK G wearer who orders a US G is ordering two cup sizes down. The cup will cut across the breast tissue at the top, the underwire will sit on tissue rather than behind it, and the band will feel tight because the cup is pulling it forward. If you want a sense of how far the ladder actually runs, the biggest bra size guide walks through the top of the range and what is genuinely manufactured.
The letter on a bra label is not a measurement. It is the name a particular country gave to a particular measurement, and two countries gave the same name to different things.
HauteFlair Editorial
Band numbers are the same in the UK and the US
UK and US band sizes are identical numbers. A 34 band in a Panache bra and a 34 band in a Le Mystere bra describe the same underbust measurement. This is the simplest fact in international bra sizing and it removes half the confusion straight away: when converting between British and American brands, only the cup letter moves.
European, French, Australian and Japanese bands are a different matter. They are not the same numbers and they do not convert with a simple sum, because European bands step in five centimetre increments while UK and US bands step in two inch increments. Use the lookup below rather than arithmetic.
| UK / US band | EU / JP band | French band | AU / NZ band |
|---|---|---|---|
| 30 | 65 | 80 | 8 |
| 32 | 70 | 85 | 10 |
| 34 | 75 | 90 | 12 |
| 36 | 80 | 95 | 14 |
| 38 | 85 | 100 | 16 |
| 40 | 90 | 105 | 18 |
| 42 | 95 | 110 | 20 |
| 44 | 100 | 115 | 22 |
| 46 | 105 | 120 | 24 |
| 48 | 110 | 125 | 26 |
French bands are the European number plus 15, so EU 75 is FR 90. Australian bands are the US number minus 22, so a US 34 is an AU 12. Everything else is a lookup, not a formula, and rounding your own arithmetic is how people end up one band out.
If you have never measured properly, do that before touching any of these charts. Our how to measure your bra size guide covers the underbust and bust measurements you need, and bra fitting covers what a correct fit actually looks like once the numbers are in.
Which of our brands use which system
Three of our houses are UK-graded and the rest are graded on the US and continental systems. Knowing which is which is the practical half of this whole article, because the conversion only matters at the moment you switch between them.
At the top of the range the field narrows sharply. In H cup our catalogue holds Panache, Panache Cleo, Panache Sculptresse, Panache Sports, Le Mystere and Dominique, and nothing else. That is not a merchandising accident. It is the direct consequence of the UK naming fifteen cup steps and building factories to grade them.
114 plus size bras and 164 full figure styles
UK houses and US houses sit side by side, so you can compare the same volume under two different letters without leaving the page.
Full figure bras Plus size brasWhy our DDD collection and our E collection are the same cup
Our DDD collection and our E collection describe the same cup volume in two different systems. We carry 16 styles filed under DDD cup bras and 39 filed under E cup bras. On the ladder, US DDD and UK E are both step 6. They are the same cup. The two collections exist because vendors label the same volume two different ways and we file each product under the letter its maker printed on it.
We would rather tell you that plainly than let you browse one collection and assume the other is a different size. If you are a US DDD, the E cup collection is also your size and it is more than twice as large. The same overlap happens one step higher: our F cup collection holds 85 styles and our G cup collection holds 66, and a US G wearer belongs in both, because US G is UK F.
The reliable move on any bra site, including ours, is to work from your bust-to-underbust difference and the brand chart on the product page rather than from the letter in the collection name. Letters are labels applied by manufacturers. Your measurement is the only number that stays constant across every system on this page.
How to convert without guessing
Convert in four steps, and identify the system before you convert rather than after. The order matters, because a conversion applied to the wrong system produces a confident, precise, wrong answer.
Measure first, in inches, snugly
Take your underbust measurement with the tape firm and level, then your bust measurement with the tape loose across the fullest point. The difference in inches is your cup step. Four inches is step 4, seven inches is step 7. That number is system-neutral and it is the only figure you should carry between charts.
Identify the brand's system before converting
Check which ladder the brand uses, then convert. Most brands publish it on their size chart, and country of origin is a strong signal when they do not: British houses grade British, American and French houses do not. If a chart lists DD followed by E followed by F followed by FF, it is UK. If it lists DD followed by DDD followed by G, it is US.
Read across the ladder, do not add letters
Find your cup step in the conversion table above and read across to the system the brand uses. Never convert by counting letters forward or backward in the alphabet, because the alphabet is exactly what the two systems disagree about. Read the row, not the letter.
Sister size sideways if the band is wrong
Sister sizing works identically in both systems. Going down one band means going up one cup step, and going up one band means going down one cup step, in the UK and the US alike. A UK 34F sisters to a UK 32FF and a UK 36E; a US 34G sisters to a US 32H and a US 36DDD. Our full guide to sister sizes works through the logic.
If the letters themselves are what is confusing you rather than the conversion, our guide to cup sizes explains what each one actually represents, and the bra sizes overview covers how a bra size is constructed from two numbers and a letter.
Where to go next, by cup
Every cup collection below is filed under the letter the manufacturer printed on the garment, which means UK and US labels sit together inside each one. Use the conversion table above first, then pick the collection that matches the letter your brand uses.
| Collection | Styles | What it holds |
|---|---|---|
| A cup bras | 56 | Same cup in every system. No conversion needed. |
| B cup bras | 105 | Same in every system. No Panache, Cleo or Sculptresse here. |
| C cup bras | 108 | Same in every system. US and European houses only. |
| D cup bras | 128 | The last identical letter, and the first cup where Panache appears. See our D cup guide. |
| DD cup bras | 47 | Step 5. UK DD and US DD agree; Europe calls it E. |
| DDD cup bras | 16 | Step 6, US label. Same cup as UK E. |
| E cup bras | 39 | Step 6, UK label. Same cup as US DDD. |
| F cup bras | 85 | UK F is step 7, the same volume as a US G. |
| G cup bras | 66 | Holds both UK G (step 9) and US G (step 7). Read the brand chart. |
| H cup bras | 122 | Panache, Cleo, Sculptresse, Panache Sports, Le Mystere and Dominique. See our H cup guide. |
| HH cup bras | 20 | UK only, step 12. Our deepest cup collection. |
Two honest gaps. We do not carry an I cup collection, because the US labels that would fill it mostly stop below that point and the UK labels that reach step 9 call it G. And our range stops at HH, so UK J, JJ and K are not stocked here. If you are above an HH, the closest thing we hold is the HH cup range in a smaller band, sister sized, and it is worth contacting us before ordering rather than guessing.
Frequently asked questions
Is a UK D the same as a US D?
Is a UK DD the same as a US DD?
What is a UK G cup in US sizes?
What is a US G cup in UK sizes?
Is a DDD the same as an E cup?
Are UK and US band sizes the same?
What is a US 34DD in European sizing?
Does sister sizing work the same way in both systems?
How can I tell which system a brand uses?
Why do British brands go so much higher up the alphabet?
Is a UK F bigger than a US F?
What is the largest cup HauteFlair stocks?
Should I size up when I switch from a US brand to a UK brand?
Do European and Japanese cups use the same letters as the US?
This guidance is general. Cup and band grading vary by brand and by style even within the same sizing system, and no conversion chart replaces the size chart printed on the product page. Always check the individual product size chart before ordering, and measure again if it has been more than a year.
