What Size Lingerie Should You Buy?
A complete lingerie size guide — UK bra sizing, briefs and knickers, bodysuits and chemises, why sizing varies between brands and how to navigate it confidently.
Lingerie sizing is more complex than clothing sizing because it varies by garment type, brand, country and even the specific style within a brand's own range. A dress size 12 tells you nothing reliable about what bra you should be wearing. Your actual measurements — underbust, bust and hips — are the only reliable starting point. This guide explains how UK lingerie sizing works across every garment category and how to navigate the inevitable variations between brands with confidence.
UK Bra Sizing: How It Works
UK bra sizing uses two numbers: a band size (the even number) and a cup size (the letter). Together they represent the size of the bra relative to the wearer's body.
Band size represents the circumference of the ribcage directly under the bust, measured in inches and rounded to the nearest even number. Common UK band sizes run from 28 to 46 in mainstream retail, with specialist brands extending further in both directions.
Cup size represents the difference in inches between the band measurement and the fullest bust measurement. In UK sizing: 1 inch difference = A cup; 2 = B; 3 = C; 4 = D; 5 = DD; 6 = E; 7 = F; 8 = FF; 9 = G; 10 = GG; 11 = H. The UK system uses double letters (DD, FF, GG, HH) between single letters to create a more gradual progression in larger sizes.
The critical point: Cup size is always relative to band size. A 32D and a 38D are completely different cup volumes, even though they share the same letter. Two people wearing the same cup letter but different band sizes are not wearing the same amount of cup volume. Cup letter alone tells you almost nothing about actual breast size.
Why Bra Sizing Varies Between Brands
There is no universal standard for lingerie sizing, and UK brands are not exempt from variation. The same cup volume may be labelled differently across brands — a size that Freya calls a 34G may be labelled 34H by Triumph, because each brand uses a slightly different cup letter progression in their extended sizes. This is not an error; it reflects the fact that each brand builds its sizing around its own patterns and fit models, which may interpret the progression of cup sizes slightly differently.
The practical implication: when buying from a new brand for the first time, do not assume your usual size translates directly. Check the brand's specific size guide, compare with your measurements, and if possible consult a brand-specific size converter. Returning to your measurements as the reference point — rather than your label size from another brand — is always the most reliable approach.
Standard and Full Bust Sizes: UK Brands
In the UK, the lingerie market is well developed for both standard (approximately cup AA to D, band 30 to 38) and full bust (cup DD and above, any band size) sizes. Major high-street brands including Marks and Spencer, John Lewis and ASOS cover both standard and fuller bust ranges. Specialist full-bust UK brands — Freya, Panache, Bravissimo, Curvy Kate, Elomi and Pour Moi — focus specifically on the fuller cup range and offer more styles and constructions designed for larger cup volumes.
The distinction between standard and full bust does not correspond to overall body size. Many people with smaller dress sizes wear larger cup sizes; many larger people wear smaller cups. The cup is determined by the relationship between the underbust and bust measurements, not by the total size of the body.
Sizing by Garment Type
| Garment | Primary Sizing Dimension | What to Measure | Notes |
|---|---|---|---|
| Bra (wired) | Band and cup (e.g. 34B) | Underbust (inches) + fullest bust (inches) | Most important garment to size accurately. Cup varies by brand — check brand-specific guides for larger cups |
| Bralette | Usually XS-XL or S/M/L | Bust measurement for reference | Most bralettes are stretch and forgiving. Fuller-bust bralettes may use band-and-cup sizing |
| Briefs and thongs | UK dress size or hip measurement | Hip circumference at fullest point | Most briefs size by hip. Between sizes, size up for comfort, down for a closer fit in stretch fabrics |
| Bodysuit (non-wired) | UK dress size / XS-XL | Bust, waist, hips; also torso length | Torso length is the most commonly missed measurement — compare with brand guidance to avoid incorrect fit at the gusset |
| Bodysuit (wired) | Band and cup | Underbust and fullest bust | Size as for a wired bra; cup fit is the priority |
| Chemise and babydoll | UK dress size / bust | Bust (primary); waist and hips less critical for flowing styles | Fuller busts should size by bust even if the rest of the garment will be slightly generous |
| Corset | Natural waist (inches) | Natural waist at narrowest point | Typically sized 4–6 inches smaller than natural waist for reduction. Brand sizing varies significantly — always check individual guidance |
| Basque (with cups) | Bra size | Underbust and fullest bust | Cup fit is primary. Many basques also give guidance on dress size for the body section |
| Suspender belt | Natural waist (inches) | Natural waist measurement | Belt should grip the waist firmly; multiple hook settings give adjustment flexibility |
UK vs European vs US Bra Sizing
UK and US bra sizing are identical up to a D cup. Above D, they diverge: UK sizing continues DD, E, F, FF, G, GG, H; US sizing varies by brand and often uses DDD (instead of E), F, G, H without the consistent double-letter progression of UK sizing. When buying from US brands, check whether they use UK or US cup progression — it matters significantly above a D cup.
European bra sizing uses centimetres for band size (rather than inches) and a different cup letter system. A EU 75B is equivalent to a UK 34B (75cm underbust = approximately 30 inches band size). Cup letters in European sizing also progress differently — EU cup D often equates to UK cup DD. Always convert when switching between UK and European brands.
Lingerie Size and Body Positivity
There is no "standard" body in lingerie, and the most important sizing principle is accuracy rather than aspiration. Buying a smaller bra size than your measurement requires does not create a smaller silhouette — it creates discomfort, potential health impacts from a too-tight band or underwire, and a garment that does not do its job. Buying the size that fits correctly produces both the best support and the most flattering appearance. UK lingerie brands now cover a wide spectrum of sizes: extended band sizes (28–46+), extended cup sizes (AA through L and beyond), plus-size ranges in all garment categories, and specialist brands focused specifically on underrepresented size ranges. Whatever your measurements, there is lingerie designed specifically for your size.
Lingerie Size Tips
Returning Lingerie in the UK
In the UK, lingerie may be returned to most retailers if it is unworn, with hygiene seals and tags intact. Wearing lingerie to assess fit and then returning it is not possible under most UK retailer return policies. This makes understanding your measurements and checking size guides before purchase particularly important. Many UK lingerie specialists offer detailed size guidance and customer service support to help you identify the right size before ordering. For bras specifically, where the fit test is most important, buying from a retailer with a clear return policy for unworn items gives you the option to order two adjacent sizes and return the one that fits less well.
For step-by-step measuring guidance, see our guide to how to measure for lingerie. Browse our full collection at Ava Noir and explore all guides at Ava Noir Lingerie Guides.
Explore Lingerie at Ava Noir
Shop lingerie in your size with confidence — discover our full collection designed for every body and every occasion.
Browse our full lingerie collection in your size at Ava Noir.
Our Lingerie Guides hub covers sizing, measuring, fit, care and choosing lingerie for every body and occasion.
Read every guide: Ava Noir Lingerie Guides.