Cup Size Comparison
Confused about the difference between a DD and an E cup, or how an A cup compares to a C? Check out the visual scaling across the complete UK cup size range below to help make sense of how cup volumes change.
Side-profile comparison of UK cup sizes AA through F. Each silhouette represents the same body with only the cup projection changing.
Select a Cup Size
Tap any cup size to see its measurement, EU equivalent and fitting notes.
UK Cup Size Measurement Table
Cup size is calculated from the difference between your full bust and your underbust measurement. UK cups differ from EU cups — this table shows both.
| UK Cup | EU Cup | Difference (cm) | Difference (inches) |
|---|---|---|---|
| AA | AA | Less than 2.5 cm | Less than 1 inch |
| A | A | 2.5 cm | 1 inch |
| B | B | 5 cm | 2 inches |
| C | C | 7.5 cm | 3 inches |
| D | D | 10 cm | 4 inches |
| DD | E | 12.5 cm | 5 inches |
| E | F | 15 cm | 6 inches |
| F | G | 17.5 cm | 7 inches |
| FF | H | 20 cm | 8 inches |
| G | I | 22.5 cm | 9 inches |
| GG | J | 25 cm | 10 inches |
| H | K | 27.5 cm | 11 inches |
| HH | L | 30 cm | 12 inches |
| J | M | 32.5 cm | 13 inches |
| JJ | N | 35 cm | 14 inches |
| K | O | 37.5 cm | 15 inches |
Important:UK cup letters and EU cup letters are not the same above a D cup. UK DD = EU E, UK E = EU F, UK F = EU G, and so on. When shopping from a European brand, always check the brand's own size guide.
Our calculator shows both your UK size and EU equivalent.
Understanding UK Cup Sizes
UK cup sizes are determined by the difference in inches between your full bust measurement and your snug underbust measurement. Each inch of difference corresponds to one cup size step — but the UK scale is unique in that it uses double letters (DD, FF, GG, HH, JJ) between each single letter, rather than skipping straight to the next.
The complete UK cup order is: AA, A, B, C, D, DD, E, F, FF, G, GG, H, HH, J, JJ, K. This is different from US sizing (which uses DDD instead of E) and EU sizing (which uses single letters throughout). If you're shopping internationally, use our bra size converter to translate.
Cup Size Is Relative to Band
One of the most misunderstood facts about bra sizing is that cup size alone tells you nothing about breast volume. A 30D and a 38D have the same cup letter but very different amounts of tissue — the 38D holds significantly more. Cup size is always relative to the band size it's paired with.
This is the concept behind sister sizes: sizes that hold the same breast volume but with different band and cup combinations (e.g., 34D, 36C, and 32DD are all sister sizes).
How to Measure Your Cup Size
- Measure snugly around your underbust (in inches) — this is your band size.
- Measure around the fullest point of your bust, keeping the tape parallel to the ground.
- Subtract underbust from bust to get the difference in inches.
- Match the difference to a cup letter: 1"=A, 2"=B, 3"=C, 4"=D, 5"=DD, 6"=E, 7"=F, 8"=FF, 9"=G.
Or skip the maths entirely with our UK bra size calculator.
UK Cup Size Quick Reference
| Difference (Inches) | UK Cup | US Equivalent | EU Equivalent |
|---|---|---|---|
| 0" | AA | AA | AA |
| 1" | A | A | A |
| 2" | B | B | B |
| 3" | C | C | C |
| 4" | D | D | D |
| 5" | DD | DD / E | E |
| 6" | E | DDD / F | F |
| 7" | F | G | G |
| 8" | FF | H | H |
| 9" | G | I | I |
| 10" | GG | J | J |
| 11" | H | K | K |
Cup Size Comparison FAQ
What is the difference between a DD and an E cup in the UK?+
In UK sizing, DD and E are two different cup sizes — DD comes before E. The UK uses double letters (DD, FF, GG) between each single letter, so the order is: D, DD, E, F, FF, G, GG, H. A DD cup has roughly 5 inches of difference between bust and underbust; an E cup has around 6 inches.
Are UK cup sizes the same as US cup sizes?+
UK and US cups are identical up to a D cup. Above D, the scales split: a UK DD equals a US DD or E, while a UK E equals a US DDD or F. See our bra size converter for a full breakdown.
Does cup size change with band size?+
Yes — cup sizes are relative to band size. A 34D holds more breast volume than a 30D, even though the cup letter is the same. This is the principle behind sister sizing: going up a band and down a cup (e.g., 34D → 36C) gives roughly the same volume with a looser band.
What does AA cup size mean?+
An AA cup is the smallest standard UK cup size, representing roughly 0 inches of difference between your underbust and full bust measurements. It indicates very little breast projection relative to the ribcage. Not all brands stock AA cups, but specialist retailers like M&S do.
How many cup sizes are in the UK range?+
The standard UK cup size range runs: AA, A, B, C, D, DD, E, F, FF, G, GG, H, HH, J, JJ, K — that's 16 cup sizes in total. Specialist brands like Bravissimo extend this even further into KK and L territory.