Why do UK bra cup sizes vary between brands?

UK bra sizing is based on a 1-inch difference between the underband and bust measurement. However, brands use different cup letter sequences to label these steps, which is why the same cup letter can represent different volumes.

Why are larger cup sizes harder to find?

Larger cup sizes require deeper cups, stronger materials and specialist design. Many mainstream brands stop at smaller sizes, so fuller-bust sizes are usually produced by specialist brands only.

Are all UK cup sizes measured the same way?

Yes. All UK bra sizing follows the same 1-inch rule. Differences between brands come from how cup sizes are labelled, not how bras are measured.

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

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

Bra Size Guides

UK Bra Cup Size Guide – Understanding Cup Sizes from F to LL

Understanding bra cup sizes can be confusing — especially once you move beyond standard high-street sizing. This hub brings together all of our UK bra cup size guides, from F cup through to LL cup, with clear explanations and brand-specific guidance.

Use this page to explore individual cup sizes, understand how UK sizing works, and find brands that genuinely make your size.

To confirm your starting size, begin with our Bra Size Calculator.

Understanding UK Cup Sizes

If you are new to UK bra sizing, these guides explain how cup sizes progress and how the sizing system works:

Bra Cup Size Chart – see the full UK cup progression and measurements.
Double Cup Bra Sizes Explained – understand sizes like FF, GG and HH.
Bra Size Calculator – calculate your starting size using band and bust measurements.

This guide focuses on UK bra cup sizes from F to LL and links to detailed explanations for each individual cup size.

How UK Bra Cup Sizes Work (F–LL Explained)

All UK bra sizing follows the 1-inch rule. Each step in the cup sequence represents a one-inch increase in the difference between the bra band size and the fullest bust measurement.

The confusion arises because not all brands use the same cup letter sequence. Some use a traditional progression, while others use an extended UK sequence that includes additional double-letter cups.

Importantly, this does not mean bras are measured differently. The difference is in how the cup steps are labelled, not how they are sized.

Because cup volume changes as band size changes, some bra sizes have closely related alternatives known as bra sister sizes. These equivalent sizes can help when the band feels too tight or too loose but the cup volume is correct.

For a visual reference of how cup sizes progress, see our UK Bra Cup Size Chart .

Extended UK cup sequence:
D, DD, E, F, FF, G, GG, H, HH, J, JJ, K, KK, L, LL

Important:
A cup size is not one fixed volume. Cup volume increases as band size increases, so a 32H and a 38H are very different in fit and capacity.

Always consider both band size and cup size together.

Browse UK Cup Size Guides

Need More Help?

If you are unsure which cup size is right for you, or if your current bras don’t fit as expected, these tools can help:

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