Why do cup sizes vary between UK bra brands?

All UK bra sizing follows the same 1-inch rule, but brands use different cup letter sequences. This means the same cup letter can represent different volumes depending on the brand.

Does band size affect cup volume?

Yes. Cup volume increases as band size increases, so a 38 cup holds more volume than the same cup letter on a smaller band.

Is UK bra sizing the same as US or EU sizing?

No. UK, US and EU sizing systems use different cup progressions. Always use a conversion chart when comparing sizes across regions.

Bra Size Guides

FF Cup Bras – Brands That Make FF Cups & How to Find Your Size

A UK FF cup is often where bra sizing starts to feel confusing. Some brands include FF as part of an extended cup sequence, while others move straight from F to G. This guide explains what FF cup really means, which brands make it, and how to find the right fit.

To confirm your starting size, begin with our Bra Size Calculator, then use the brand guidance below to shop confidently.

Who This Guide Is For

Women who wear a UK FF cup
Those moving up from F and unsure what comes next
Shoppers confused by FF vs G sizing
Anyone comparing traditional and extended UK cup sequences
People struggling with inconsistent fit between brands

Why Not All FF Cup Bras Are the Same

Although FF cup is a recognised UK bra size, not all FF cups have the same volume. This is because different UK cup letter sequences are used by different brands, even though the underlying sizing rule is the same.

Bra cup sizes are determined by the difference between the band size and the fullest bust measurement. Each increase of 1 inch in that difference equals one cup size in the UK sizing system.

The difference between brands is not how the size is calculated, but which letters are used to label each step. Traditional UK brands follow a shorter sequence: B, C, D, DD, E, F, G, H, J, K.

Fuller-bust specialist brands use an extended UK cup sequence that includes additional double letters: D, DD, E, F, FF, G, GG, H, HH, J, JJ, K, KK, L, LL.

Each step in the UK cup size sequence represents a 1 inch increase in the difference between the underband and the fullest bust measurement. This rule applies to all UK brands, regardless of whether they use a traditional or extended cup letter sequence.

The only difference between brands is how those 1-inch steps are labelled. Traditional-sequence brands move directly from F to G, while extended-sequence brands include FF as a distinct step between F and G. The measurements increase in exactly the same way — only the letters change.

This difference is not related to support, quality or construction. It is simply the result of using different cup letter progressions. Both systems are valid UK sizing methods, but they are not interchangeable by letter alone.

Important:
A cup size is not one fixed volume. Cup volume increases as the band size increases, so a 30FF, 34FF and 40FF are all very different in fit and capacity, even though the cup letter is the same.

Always consider both band size and cup size together when comparing bras.

UK Brands That Make FF Cup Bras

FF cup bras are typically found in fuller-bust specialist brands that use an extended UK cup sequence. The brands below have confirmed FF cup availability.

Bravissimo – Bands 28–40, cups D–L View size guide
Freya – Bands 28–42, cups B–K View size guide
Panache – Bands 28–46, cups B–K View size guide
Sculptresse – Bands 34–46, cups D–K View size guide
Goddess – Bands 32–56, cups B–K View size guide

FF Cup Band Sizes by Brand

Based on confirmed brand availability tables, these are the UK band sizes typically available in an FF cup. Availability may vary by style.

Bravissimo: 28FF, 30FF, 32FF, 34FF, 36FF, 38FF, 40FF
Freya: 28FF, 30FF, 32FF, 34FF, 36FF, 38FF, 40FF, 42FF
Panache: 28FF, 30FF, 32FF, 34FF, 36FF, 38FF, 40FF, 42FF, 44FF, 46FF
Sculptresse: 34FF, 36FF, 38FF, 40FF, 42FF, 44FF, 46FF
Goddess: 32FF, 34FF, 36FF, 38FF, 40FF, 42FF, 44FF, 46FF, 48FF, 50FF, 52FF, 54FF, 56FF

How to Find Your Correct FF Cup Size

Measure your underband and bust carefully, then enter your measurements into our Bra Size Calculator to get a recommended UK starting size.

For measuring tips and fit checks, see our Bra Fitting Advice.

FF Cup Bra FAQs

Is FF bigger than F?
Yes. In extended UK sizing, FF is one cup step larger than F and one step smaller than G.

Do all brands offer FF cups?
No. FF is mainly used by fuller-bust specialist brands that follow an extended UK cup sequence.

Does band size affect FF cup volume?
Yes. A 38FF holds more volume than a 32FF, even though the cup letter is the same.

FF cup sits between F and G in extended UK sizing. If you're deciding between sizes, it can help to compare F cup bras and G cup bras to find the best fit.

Related Cup Size Guides

For general background on bra sizing systems, see the bra size reference on Wikipedia .