Bra Size Guides

UK and US bra sizing systems use different cup letter progressions, which can make the same size appear different depending on the brand. This guide explains how UK and US sizing compare, why confusion happens, and how to check whether a cup letter represents the same volume.

Understanding the differences between UK vs US bra sizes helps prevent ordering the wrong cup letter when shopping internationally.

If you are unsure of your starting size, confirm your measurements first using our Bra Size Calculator. Then review the sizing systems below before purchasing internationally.

Why UK and US Bra Sizes Are Different

Both UK and US bras follow the same fundamental sizing principle: cup size increases as the difference between the band size and the fullest bust measurement increases. However, the letter sequence used to label each step is not always the same.

UK brands commonly use an extended cup sequence that includes double letters such as FF, GG, HH and JJ. Many US brands use a different progression after D or DD, often skipping certain double letters or using DDD instead.

UK vs US Bra Sizes: UK Extended Cup Sequence

D, DD, E, F, FF, G, GG, H, HH, J, JJ, K, KK, L, LL

UK vs US Bra Sizes: US Cup Sequence

D, DD, DDD (F), G, H, I, J, K, L, M, N, O

Because of these differences, a UK H cup may not represent the same cup volume as a US H cup from a brand that follows a different progression.

Typical UK to US Cup Letter Comparison

The table below shows a general comparison between extended UK cup letters and commonly used US cup letters. Exact equivalence can vary by brand.

UK Cup Common US Equivalent
DD
DDDD
EDDD / F
FG
FFH
GI
GGJ
HK
HHL
JM
JJN
KO
Important:
Many UK-based fuller-bust brands such as Panache, Freya, Fantasie and Elomi use the same extended UK cup sequence internationally. In those cases, the cup letters remain the same across UK and US labels.

Always check the brand’s sizing system before comparing sizes.

Do Band Sizes Differ Between UK and US?

UK and US band sizes generally use the same numerical system (30, 32, 34, 36, etc.). However, how brands recommend measuring and selecting a band can vary. Fit should always be assessed by how the bra sits on the body rather than relying solely on tape measurements.

How to Compare UK vs US Bra Sizes Safely

  • Confirm whether the brand follows UK or US sizing.
  • Check whether the brand uses extended double-letter cups.
  • Compare cup progression, not just the letter itself.
  • Use brand size charts rather than assuming equivalence.

For brand-specific guidance, visit our Brand Size Guides .

UK vs US Bra Size FAQs

Is a UK H cup the same as a US H cup?
Not always. Many UK-based fuller-bust brands use the same extended cup lettering internationally. However, some US brands follow a different cup progression. Always check the brand’s sizing system rather than relying on the letter alone.

Why do UK bras use double letters like FF and GG?
UK sizing includes additional double letters within the cup sequence. These letters still represent standard 1-inch cup increments. The difference is in how the cup steps are labelled, not in how volume is calculated.

Do UK and US band sizes differ?
Band numbers are generally the same in both systems (30, 32, 34, etc.), but fit can vary between brands. Always assess how the band fits on your body rather than relying solely on numbers.

What is the US equivalent of a UK GG cup?
In many US sizing systems, a UK GG cup is roughly equivalent to a US J cup. However, this can vary depending on how the brand structures its cup progression.

Is an FF cup bigger than an F cup?
Yes. In UK sizing, an FF cup is one cup size larger than an F cup. Double letters such as DD, FF and GG are simply additional steps within the UK cup sequence. Each step still represents a standard 1-inch increase in cup volume.

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

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