UK Bra Size Calculator & Converter
Calculate your UK bra size in inches, decode the DD+ cup alphabet (DD, E, F, FF, G, GG…), and convert instantly to US, AU, EU & FR — with sister sizes and Bravissimo, Panache & M&S fit notes.
How to measure correctly
- Wear a non-padded bra or no bra for accurate readings.
- Underbust: wrap tape snugly around your ribcage directly under the bust. Keep tape parallel to the floor. Exhale fully and measure.
- Overbust: measure around the fullest part of your bust. Tape should be loose enough to slide a finger underneath.
- Stand naturally — don’t lift arms or lean forward. Both measurements taken in the same posture.
- Round to the nearest 0.5 cm (or ¼ inch) for best accuracy.
International Size Conversions
Your Sister Sizes (Same Cup Volume)
Recommended Bras in Your Size
Hand-picked UK brands verified for correct sizing. Ships to UK and internationally.
- UK bands 28–46, cups A–K
- Three-section cup for full bust support
- Side boning, wide-set straps
- Smooth finish under any fabric
- Available D–GG in extended bands
- Panache, Freya, Fantasie styles
Measure correctly to get your accurate UK bra size
What Is the UK Bra Sizing System?
UK bra sizing uses inch-based band numbers (28, 30, 32, 34, 36, 38…) paired with an extended unique-letter cup alphabet (A, B, C, D, DD, E, F, FF, G, GG, H, HH, J, JJ, K). Band size is calculated from your underbust measurement in centimetres — 68–72 cm equals a UK 34. Cup size is the difference between overbust and underbust, with each letter representing roughly 2.5 cm of additional volume. UK sizing is the most logically consistent system for D+ cups, making it the global standard for specialist full-bust retailers like Bravissimo, Panache, Freya, and Curvy Kate.
The UK bra sizing system is widely considered the clearest framework for full-bust sizing in the world. Unlike the US system — which resorts to doubled letters like DDD and DDDD past D cup — the UK assigns a unique letter to every cup size. DD is followed by E, then F, FF, G, GG, H, HH, J, JJ, K. This unambiguous progression means a UK GG cup is instantly recognisable as a specific volume, whereas its US equivalent (I or J cup, depending on the brand) creates confusion even among experienced shoppers.
Band size logic is straightforward. Your underbust measurement in centimetres maps directly to a band number: 63–67 cm gives UK 30, 68–72 cm gives UK 32, 73–77 cm gives UK 34. Each band spans 5 cm. Unlike the legacy US system — which historically added four or five inches to the underbust measurement before calculating cup size — the modern UK method works directly from the measurement, producing a more anatomically accurate result.
Cup size is calculated as the difference between your fullest bust measurement and your underbust. Each 2.5 cm of difference corresponds to one cup letter step. A 19–21 cm difference is a D cup. A 22–23 cm difference is DD. A 24–26 cm difference is E. This consistent 2.5 cm grading continues all the way through K cup, providing a reliable reference regardless of band size.
UK bands follow underbust centimetres directly — no arbitrary inch offset applied.
UK cup letters show relative volume — each step is approximately 2.5 cm of additional overbust–underbust difference.
- UK band sizes are inch-based: 28, 30, 32, 34, 36, 38, 40, 42, 44, 46
- UK uses unique cup letters past D: DD, E, F, FF, G, GG, H, HH, J, JJ, K — never DDD
- UK 34 = AU 12 = EU 75 — all describe an underbust of 73–77 cm
- UK cup letters are identical to Australian cup letters — same system, same progression
- The UK system is the global standard for specialist D+ cup retailers worldwide
How to Measure Your UK Bra Size
You need two measurements: your underbust (the rib cage directly below the breast) and your overbust (the fullest part of the bust). A soft tape measure and five minutes will get you within one sister size of your perfect fit.
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Prepare correctly
Wear a non-padded bra or no bra. Padded bras add 2–4 cm to your overbust measurement, shifting your cup size reading by one or two letters. Stand in front of a mirror with arms relaxed at your sides.
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Measure your underbust
Wrap the measuring tape snugly around your ribcage directly beneath your bust. The tape must be parallel to the floor all the way round — not dipping at the back. Exhale fully and record the measurement in centimetres. This determines your UK band size.
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Measure your overbust
Measure around the fullest point of your bust. Keep the tape horizontal and loose enough to slide one finger underneath — you want the natural shape, not compressed. Record in centimetres.
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Calculate your UK band
Match your underbust to the UK band chart: 63–67 cm = UK 30, 68–72 cm = UK 32, 73–77 cm = UK 34, 78–82 cm = UK 36, 83–87 cm = UK 38. If you fall on a boundary, try both — most fitters recommend starting with the smaller band.
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Calculate your cup letter
Subtract underbust from overbust. Match the difference to the UK cup chart: 11–13 cm = A, 14–16 cm = B, 17–18 cm = C, 19–21 cm = D, 22–23 cm = DD, 24–26 cm = E, 27–28 cm = F, 29–31 cm = FF, 32–33 cm = G, 34–36 cm = GG. Each step is approximately 2.5 cm.
Remeasure every six months, or after any weight change of 3+ kg, pregnancy, breastfeeding, or notable changes in how your current bras feel. Most UK bra fitters — including Bravissimo’s trained consultants — recommend measuring twice a year as standard practice. Your rib cage measurement changes with weight, hormonal cycles, and age, independent of your chest size.
Skip the calculation — use the calculator
Enter your measurements once and get your exact UK size plus conversions to US, AU, EU, FR, and IT instantly.
Open the UK Bra Size Calculator →UK Bra Size Chart (Underbust cm Reference)
This chart is the standard UK sizing reference used by Bravissimo, Panache, Freya, Marks & Spencer, and ASOS. It is also the methodology used by the UK lingerie trade association for professional bra fitting certification.
UK sizes compared with US, AU, and EU systems
| UK Band | Underbust (cm) | Underbust (in) | AU Band | EU Band | FR Band |
|---|---|---|---|---|---|
| UK 28 | 58–62 | 23–24.5 | AU 6 | 65 | 80 |
| UK 30 | 63–67 | 25–26.5 | AU 8 | 70 | 85 |
| UK 32 | 68–72 | 26.5–28.5 | AU 10 | 75 | 90 |
| UK 34 | 73–77 | 28.5–30.5 | AU 12 | 80 | 95 |
| UK 36 | 78–82 | 30.5–32.5 | AU 14 | 85 | 100 |
| UK 38 | 83–87 | 32.5–34.5 | AU 16 | 90 | 105 |
| UK 40 | 88–92 | 34.5–36 | AU 18 | 95 | 110 |
| UK 42 | 93–97 | 36.5–38 | AU 20 | 100 | 115 |
| UK 44 | 98–102 | 38.5–40 | AU 22 | 105 | 120 |
| UK 46 | 103–107 | 40.5–42 | AU 24 | 110 | 125 |
UK Cup to US, AU, EU Cup Conversion
The UK cup letter system is the most internationally adopted standard for D+ sizing, but direct conversion to US and EU labels above D cup trips up even experienced shoppers. A UK E cup is labelled DDD in the US and F in the EU — the same breast volume, three completely different labels. Understanding this mapping is essential when buying from any non-UK retailer.
| UK / AU Cup | US Cup | EU Cup | JP / KR Cup | Overbust − Underbust (cm) |
|---|---|---|---|---|
| AA | AA | AA | AA | 8–10 cm |
| A | A | A | A | 11–13 cm |
| B | B | B | B | 14–16 cm |
| C | C | C | C | 17–18 cm |
| D | D | D | D | 19–21 cm |
| DD | DD | E | E | 22–23 cm |
| E | DDD | F | F | 24–26 cm |
| F | DDDD / G | G | G | 27–28 cm |
| FF | G / H | H | H | 29–31 cm |
| G | H / I | I | — | 32–33 cm |
| GG | I / J | J | — | 34–36 cm |
| H | J / K | K | — | 37–38 cm |
| HH | K / L | L | — | 39–41 cm |
| J | L / M | M | — | 42–43 cm |
| JJ | M / N | N | — | 44–45 cm |
Many shoppers believe UK DD is a “very large” cup. It is not. DD is the fifth cup letter in the UK sequence — one step above D and equivalent to a 22–23 cm difference between overbust and underbust. The UK system has ten additional cup sizes above DD (E through JJ), making DD a mid-range size, not an extreme one. This misconception is one of the main reasons D+ women underestimate their cup size when measured.
What Are Sister Sizes in UK Bras?
Sister sizes are bra sizes that share the same cup volume but carry different band widths. They are your most practical tool for shopping across brands, dealing with stock gaps, and fine-tuning fit when a bra is almost right but not quite.
The sister size rule
When you change the band by one size, you must change the cup letter by one step in the opposite direction to maintain the same cup volume:
- Smaller band, larger cup letter: If your 34E band rides up, try 32F. Same volume, tighter band.
- Larger band, smaller cup letter: If your 34E band digs in, try 36DD. Same volume, looser band.
UK 34E sister size example
| Size | Band Feel | Cup Volume | When to Try It |
|---|---|---|---|
| UK 32F | Tighter | Same | Your 34E band rides up or feels loose |
| UK 34E | Standard | Same | Your primary size |
| UK 36DD | Looser | Same | Your 34E band digs in or feels tight |
Bravissimo, Panache, and Freya each grade their bands slightly differently. A Bravissimo 34E may feel firmer than a Panache 34E from the same label. Knowing your sister sizes — 32F and 36DD in this case — gives you immediate fallback options without losing cup volume. This is particularly important for D+ shoppers where stock in any single size is often limited.
Different breast shapes require different bra fits — UK specialist brands excel at extended cup fitting
UK Bra Brand Sizing Differences
Even within UK sizing, not all brands grade cups and bands identically. Here is how the major UK and internationally-stocked brands run compared to the standard UK chart.
Bravissimo UK
The UK’s leading D+ specialist. Bravissimo’s sizing follows the strict UK standard and its in-store fitting methodology is used as the benchmark by many UK fitters. Stocks bands 28–40 in cups D–L.
Fit: True to UK size. The gold standard for D+ fit. No adjustment needed.
Panache UK
Award-winning British brand known for structured, supportive underwire styles. Panache bands run firm — most wearers find them half a size tighter than the label suggests on first wear.
Fit: Bands run slightly firm. If your Panache 34E feels tight in the band, try 36DD before sizing up the cup.
Freya UK
Freya specialises in D–K cup with an extensive range of styles from balconette to sports. Known for generous cup grading — cups tend to run slightly larger than the UK standard.
Fit: Cups run slightly generous. If your usual size gaps in the cup, try one cup letter down.
Curvy Kate UK
Specialists in D–K cups with a focus on style and comfort. Curvy Kate bands run true to the UK standard; their cups are graded to accommodate fuller, rounder shapes.
Fit: True to UK band. Cups suit rounder breast shapes — if you have a shallower profile, size down one cup.
Marks & Spencer UK
M&S is the most widely shopped bra retailer in the UK. Their own-label range covers AA–GG cups in bands 30–44. Sizing is generally true to the UK chart for standard styles.
Fit: True to UK size in wired styles. Soft-cup and T-shirt bras occasionally run a cup shallow — size up if in doubt.
Victoria’s Secret US
Uses US labelling — 32, 34, 36 bands and A, B, C, D, DD, DDD cups. Does not stock above DDD (UK E equivalent). Bands run small and cups run generous versus US label.
Fit tip: If you’re UK 34E, you’re out of VS range. UK 34DD = US 34DD. UK 34D = US 34D. Go up one band if VS band feels tight.
Calvin Klein US
US-labelled sizes. Known for firm bands and shallower cups than equivalent UK sizing. Limited range above DD cup. Popular for everyday T-shirt bras in smaller cup sizes.
Fit tip: Bands run tight — size up one band from your UK size. Cups run shallow — size up one cup if you’re a D or above.
ASOS UK
ASOS stocks own-label and third-party brands. Own-label sizing follows the UK chart in bands 28–46, cups A–GG. Third-party brands follow their own country’s sizing system.
Fit: ASOS own-label is true to UK size. Check brand origin on third-party products — US brands will be labelled US, EU brands EU.
Signs Your UK Bra Size Is Wrong
Even with correct measurements, fit can drift with different brands or over time. Here is how to diagnose a poor fit and which adjustment to make.
Band size problems
- Band rides up at the back: band is too big. Try one band down, one cup up (e.g., UK 34E → 32F).
- Band digs into ribs or leaves deep red marks: band is too small. Try one band up, one cup down (e.g., UK 34E → 36DD).
- Band pulls forward when you raise your arms: band is too loose or not sitting level. Tighten hooks or size the band down.
- Straps falling off constantly: usually a band problem — a correctly fitted band carries 80% of support, not the straps.
Cup size problems
- Breast tissue spilling over the top or sides of the cup: cup too small. Size up one letter (e.g., UK 34E → 34F).
- Gaping or wrinkling fabric in the cup: cup too big. Size down one letter (e.g., UK 34E → 34DD).
- Underwire sitting on breast tissue instead of flat on the ribcage: cup too small. Size up one letter immediately.
- Centre gore not lying flat against your sternum: cup too small or wrong cup shape for your breast root width.
If you’ve been wearing the same size for more than two years without measuring, you are almost certainly in the wrong size. UK bra fitting studies consistently show that 80% of women are wearing an incorrectly sized bra — most are in a band that is too large and a cup that is too small. Rib cage volume changes with age, weight fluctuations, pregnancy, and hormonal cycles. Your bra needs to change with you.
Why UK Bra Sizing Confuses Everyone
UK bra sizing is actually one of the most logical systems in the world — the confusion arises almost entirely from how it interacts with the US system, and from one persistent myth about what “large” cup sizes mean.
The DD ceiling myth
The most damaging misconception in UK bra sizing is that DD is the largest available cup. This was true in the 1950s and 1960s, when UK manufacturers stopped grading at DD. Bravissimo’s founding in 1995 — and its subsequent creation of the extended UK alphabet through JJ and K — permanently changed this. Today the UK system covers 15 distinct cup letters from AA to K. DD is the fifth letter. The idea that D or DD is “large” causes an estimated 70% of D+ cup women to wear an incorrect (too small) cup size.
US cup labels above D
When US shoppers encounter UK sizing online, the cup letters above D look unfamiliar — E, F, FF, G, GG. The US equivalent for a UK E is DDD, and for a UK FF is G or H depending on the brand. This creates real confusion when UK-based retailers (ASOS, NEXT, John Lewis) ship to international customers. UK retailers increasingly list both UK and US cup labels in their size guides to address this, but inconsistency remains.
The three-label problem for UK shoppers
A UK shopper with a 34E might encounter these labels across different retailers:
- 🇬🇧 Bravissimo: 34E
- 🇺🇸 Victoria’s Secret: Out of range (max US DDD = UK E, but VS doesn’t stock this band/cup combo)
- 🇩🇪 Triumph Germany: 75F
- 🇫🇷 Chantelle: 90F
- 🇦🇺 Berlei Australia: AU 12E
Our approach treats the UK system as the authoritative global reference for cup size logic, then converts outward to other systems. UK cup letters provide a unique identifier for every cup volume from AA to K — 15 distinct sizes with no ambiguity. We map each UK cup to its US, EU, AU, FR, IT, and JP equivalents using direct centimetre-difference data, not brand-specific guesswork. This produces the most accurate international conversion available from raw measurements.
Shopping International Brands as a UK Shopper
Buying imported bras online is the fastest way for UK shoppers to end up in the wrong size. Each labelling system has quirks that catch even experienced buyers out.
Buying from US retailers
Convert your UK band directly — UK 32 = US 32, UK 34 = US 34. For cups up to D, the labels are identical. Above D: UK DD = US DD, but UK E = US DDD, UK F = US DDDD or G (brand-dependent), UK FF = US G or H. US retailers rarely stock above G or H cup in their domestic labelling, which cuts off UK E+ wearers entirely from brands like Victoria’s Secret and Calvin Klein. If you’re UK E or above, stick to specialist UK or EU retailers when shopping online from the US.
Buying from Australian retailers
This is the easiest conversion. UK and Australian cup letters are completely identical — the only change is the band number. UK 34 = AU 12, UK 36 = AU 14, UK 38 = AU 16. Your cup letter stays exactly the same. A UK 34FF is an AU 12FF with no other adjustment required. Berlei, Bras N Things, and Bonds all use this system.
Buying from European retailers
EU band numbers are in centimetres. UK 32 (68–72 cm underbust) = EU 75. UK 34 = EU 80. UK 36 = EU 85. EU cup letters run one letter above UK/AU for sizes D and above: UK DD = EU E, UK E = EU F, UK F = EU G, UK FF = EU H. French brands (Chantelle, Simone Pérèle, Aubade) add 15 to the EU band: UK 34F = EU 80G = FR 95G.
Always check the brand’s specific size chart before purchasing from an international retailer. Even within the same country, individual brands have sizing quirks. Look for customer reviews that mention the reviewer’s usual size — “I’m normally a UK 34E and took my usual size” is more useful than any generic size guide the brand publishes.
Recommended Bras for UK Sizing
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- UK bands 28–46, cups D–K
- Three-section cup, side boning
- Panache, Elomi, Fantasie styles
- Smooth finish, no visible seams
- Available D–GG in extended bands
- Freya, Chantelle, Wacoal styles
- Wire-free comfort, full coverage
- Bands 30–44, cups A–H
- Triumph, Sloggi, Berlei styles
- Encapsulation design for D–K cups
- Bands 30–44 in standard UK sizing
- Panache Sport, Freya Active styles
Frequently Asked Questions
UK bra sizing uses inch-based band numbers (28, 30, 32, 34, 36, 38…) calculated from your underbust measurement in centimetres, paired with a unique-letter cup alphabet (A, B, C, D, DD, E, F, FF, G, GG, H, HH, J, JJ, K). Each cup letter represents approximately 2.5 cm of difference between your overbust and underbust. The UK system is the global standard for specialist D+ cup fitting, used by Bravissimo, Panache, Freya, Curvy Kate, and Marks & Spencer.
UK and US band numbers are identical — UK 34 equals US 34. Cup letters match up to D cup: UK A = US A, UK B = US B, UK D = US D. Above D cup the systems diverge: UK DD = US DD, UK E = US DDD, UK F = US DDDD or G, UK FF = US G or H, UK G = US H or I. US retailers rarely stock above H cup, so UK E+ wearers often find US brands cannot accommodate their size.
UK cup E equals US cup DDD. The UK uses a unique-letter system (DD, E, F, FF, G, GG) where each letter represents approximately 2.5 cm of additional cup volume, while the US doubles letters instead (DD, DDD, DDDD) before switching to alphabetical. A woman wearing a UK 34E has a 24–26 cm difference between her overbust and underbust. Her US equivalent is 34DDD. Her EU equivalent is 75F. Her Australian equivalent is AU 12E — cup letters are identical between UK and Australia.
The cup letter system is completely identical — UK and Australia both use the extended alphabet (A, B, C, D, DD, E, F, FF, G, GG, H, HH). Only the band number differs. UK bands use inch-based numbers (28, 30, 32, 34, 36) while Australian bands use dress-size numbers (6, 8, 10, 12, 14). UK 34 equals AU 12. UK 36 equals AU 14. If you know your UK cup letter, it is exactly the same letter in Australian sizing — no conversion needed for the cup.
Both use the standard UK system, but with important differences in how their bands and cups grade. Bravissimo’s bands follow the UK standard precisely and are generally true to size. Panache bands tend to run firm — many wearers find a Panache 34E feels half a size tighter than a Bravissimo 34E in the band. If your Panache band feels tight, try 36DD before sizing up the cup. Panache cups are consistent with the UK standard; Freya cups tend to run slightly generous.
UK bands are inch-based numbers (32, 34, 36) while EU bands are centimetre-based (75, 80, 85). UK 34 = EU 80. UK 36 = EU 85. For cup letters, they match through D cup, but above D the EU runs one letter higher: UK DD = EU E, UK E = EU F, UK F = EU G, UK FF = EU H, UK G = EU I. France adds 15 to the EU band number — so UK 34F = EU 80G = FR 95G. Germany and Spain use standard EU numbering.
Sister sizes are UK bra sizes that share the same cup volume but have different band widths. To find your UK sister sizes, go up one band and down one cup letter, or down one band and up one cup letter. For example, UK 34E shares its cup volume with UK 32F (tighter band) and UK 36DD (looser band). Sister sizes are essential for shopping at Panache, Freya, and Bravissimo, where stock in specific sizes is often limited and your sister size provides a guaranteed volume-equivalent alternative.
A correctly fitted UK bra has a band that sits level, firmly, and parallel to the floor — it should not ride up when you raise your arms. The underwire should sit flat against your ribcage, not on breast tissue. The cups should contain all breast tissue with no spillage over the top or sides. The centre gore should lie flat against your sternum. Straps should sit comfortably without digging in or falling off. If any of these signs are off, try a sister size or consult a Bravissimo or M&S fitting service.
Every six months at minimum, or any time you experience weight change of 3 kg or more, pregnancy, breastfeeding, hormonal shifts such as starting or stopping contraception, or noticeable changes in how your current bras fit. UK bra fitting research consistently shows that most women have not been measured in over two years. Your rib cage circumference — which determines your UK band size — changes with weight, posture, and age independently of your cup size.
If your underbust falls exactly on a boundary — for example, 73 cm is the upper edge of UK 32 (68–72 cm) or the lower edge of UK 34 (73–77 cm) — try the smaller band first. Bra bands stretch with wear, so a band that feels slightly firm when new will relax to a comfortable fit within a week of regular wear. If the smaller band feels genuinely restrictive after a few days, size up. UK specialists like Bravissimo recommend starting with the tighter band as standard practice for this reason.
Industry data from UK retailers consistently places UK 36D and UK 34D as the most commonly sold sizes, though this reflects purchasing behaviour at mainstream retailers rather than anatomical averages. Bravissimo’s customer data suggests the average size among D+ cup shoppers is closer to 34E or 34F. The widespread myth that DD is a large cup leads many women to buy a smaller cup than they need, skewing mainstream sales data toward smaller cups. UK 36D is likely an underestimate of the true average cup size.
UK specialist retailers stock considerably larger sizes than high-street chains. Bravissimo stocks bands 28–40 in cups D through L (UK labelling). Fantasie and Elomi extend through K and L cup with bands to 46. For very large sizes, specialist online retailers like Bravissimo, Figleaves, and Burvogue stock through N cup and band size 50 or beyond. Marks & Spencer and ASOS generally stop at GG cup — if you’re above GG, a specialist retailer will serve you significantly better than any high-street chain.
UK bra sizing uses inches for its band number labels (UK 32, 34, 36), but modern UK fitters and calculators — including this one — work from centimetre raw measurements for greater precision. Your underbust measurement in centimetres maps directly to a UK band number: 73–77 cm = UK 34, 78–82 cm = UK 36. Working in centimetres eliminates the rounding errors introduced by inch-based measurement. The Bra-Calculator.com UK calculator accepts both centimetres and inches for your convenience.
Related Calculators & Guides
- Australian Bra Size Calculator
- US Bra Size Calculator
- EU Bra Size Calculator
- India Bra Size Calculator
- Japan Bra Size Calculator
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- Global Bra Size Converter
- Free Bra Size Calculator
- Sister Size Calculator
- Cup Size Calculator
- Complete Bra Size Chart
- How to Measure Bra Size
- Common Bra Fit Problems
- Breast Shape Identifier
- AI Smart Fit Bra Calculator
- Cup Size Visual Guide
- Bra Fit Problem Solver
- How to Know If Your Bra Fits
- 34B Bra Size Guide
- 36C Bra Size Guide
- 32C vs 34B Sister Size Guide
- 34D vs 36C Comparison
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