Cup size chart
Cup size comes from the difference between your bust and your band. This chart lines up US, UK and EU cup letters so you can convert above a D cup, where the systems part ways.
| Bust minus band (in) | US cup | UK cup | EU / AU cup |
|---|---|---|---|
| 1 | A | A | A |
| 2 | B | B | B |
| 3 | C | C | C |
| 4 | D | D | D |
| 5 | DD | DD | E |
| 6 | DDD / F | E | F |
| 7 | G | F | G |
| 8 | H | FF | H |
| 9 | I | G | I |
| 10 | J | GG | J |
| 11 | K | H | K |
Up to a D cup the three systems agree, but beyond it they diverge in a way that trips up a lot of shoppers. The US system doubles letters, going D, DD, DDD, then moving to G, H and so on. The UK inserts extra double letters, going D, DD, E, F, FF, G. The EU runs a clean single sequence, D, E, F, G, H. That is why a US DDD, a UK E and an EU F all describe the same cup.
Cup size is meaningless without a band, since the same cup letter holds a different volume on a 30 band than on a 40 band. Use the bra size calculator to get band and cup together, and see the full bra size chart for band conversions.
Cup size questions
How is cup size measured?
Cup size is the difference between your bust measurement and your band measurement. Each inch of difference is about one cup letter, so a one inch difference is an A and a five inch difference is a DD in the US system.
What is a US DD in UK and EU sizes?
A US DD is a UK DD and an EU E. Above a D cup the systems diverge: the US doubles letters (DD, DDD) while the UK inserts extra letters (DD, E, FF) and the EU runs straight through (E, F, G).
Is a UK cup the same as a US cup?
Up to a D they match, but above that they differ. A US G is a UK F, for example. Always convert rather than assume the letter carries across.
Last reviewed and updated on July 2, 2026. Conversion tables are checked against published international sizing standards.