Bra Cup Size Guide (UK) | F to LL Cup Sizes Explained & Compared
Understanding bra cup sizes in the UK can be confusing, especially when comparing different cup sizes across the fuller-bust range.This guide focuses on fuller-bust sizes (F to LL), with additional cup sizes added over time.
In the UK bra sizing system, cup size is determined by the difference between your band size and your fullest bust measurement. Each increase in cup letter typically represents about a 1 inch difference.
If you are unsure of your starting size, you can use our Bra Size Calculator, check your fit using our Bra Fitting Advice, and compare sizes across brands with our Bra Size Converter.
Fuller-bust cup sizes typically progress as F → FF → G → GG → H → HH → J → JJ → K → KK → L → LL. Each step represents a gradual increase in cup volume, but the actual size also depends on the band measurement.
What Do Different Cup Sizes Look Like?
Many people searching for a bra cup size guide are trying to understand how different cup sizes compare visually. Because cup size depends on both the band size and cup letter, the appearance of each size can vary.
For example, a 32G will have less overall volume than a 38G, even though the cup letter is the same. This is why comparing sizes across different band measurements helps give a clearer understanding of cup size progression.
For detailed breakdowns of individual sizes, explore the guides below or use our Bra Fitting Advice.
Bra Cup Size Guide UK: How Cup Sizes Work
Cup size is not a fixed volume. A 30F, 34F and 40F all represent different breast volumes because cup size increases with band size. This is why bra sizing always combines both the band size and cup size.
For example, a 34G has a similar cup volume to a 32GG and a 36FF. These are known as sister sizes. You can learn more in our Bra Sister Sizes Explained guide.
F to LL Cup Size Guides
Explore each cup size below to understand how it compares within the UK bra sizing system. Each guide explains measurements, volume and examples across band sizes.
- F Cup – size and measurements
- FF Cup – size and measurements
- G Cup – size and measurements
- GG Cup – size and measurements
- H Cup – size and measurements
- HH Cup – size and measurements
- J Cup – size and measurements
- JJ Cup – size and measurements
- K Cup – size and measurements
- KK Cup – size and measurements
- L Cup – size and measurements
- LL Cup – size and measurements
For a complete overview of sizes from F to LL, see our bra cup size guide.
If you are comparing nearby sizes, you can also explore guides such as G vs GG vs H or H vs HH vs J.
Comparing Cup Sizes
- F vs FF vs G Cup Size
- G vs GG vs H Cup Size
- H vs HH vs J Cup Size
- J vs JJ vs K Cup Size
- K vs KK vs L Cup Size
- L vs LL Cup Size
Bra Cup Size Guide FAQs
Cup size is based on the difference between your band measurement and your bust measurement. Each cup size represents roughly a 1 inch increase in this difference.
Yes. In the UK bra sizing system, cup sizes progress from G to GG, meaning a GG cup is one cup size larger than a G cup.
No. Cup volume increases with band size, so a 30F is smaller in volume than a 38F, even though the cup letter is the same.
Find Your Correct Bra Size
To find your correct size, start with our Bra Size Calculator.
You can then check your fit using our Bra Fitting Advice and compare sizes across brands using the Bra Size Converter.
For additional background on bra sizing, you may find this bra size reference useful.