Cup Size Guide (US/UK)
Each inch of difference between your bust and your band size adds one cup. UK and US letters match up to D and then split. EU cups are listed as the letter a brand would print on the same bra.
| Bust-Band Diff. | UK Cup | US Cup | EU / FR Cup |
|---|---|---|---|
| 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 |
Above about an H cup the letters used by UK, US and EU brands drift apart, and some EU brands skip the letter I. Check the size chart of the brand you are buying.
Band Size Conversion
| US/UK | EU (cm) | FR/ES/BE | AU/NZ | Typical underbust |
|---|---|---|---|---|
| 28 | 60 | 75 | 6 | 27-28 in |
| 30 | 65 | 80 | 8 | 29-30 in |
| 32 | 70 | 85 | 10 | 31-32 in |
| 34 | 75 | 90 | 12 | 33-34 in |
| 36 | 80 | 95 | 14 | 35-36 in |
| 38 | 85 | 100 | 16 | 37-38 in |
| 40 | 90 | 105 | 18 | 39-40 in |
| 42 | 95 | 110 | 20 | 41-42 in |
| 44 | 100 | 115 | 22 | 43-44 in |
This is the label conversion brands use: a UK 32 band is sold as 70 in most of Europe and 85 in France. It is not the same as measuring in centimeters under the European standard EN 13402, which uses your underbust rounded to 5 cm and 2 cm steps per cup. Because the UK and US bands were historically based on "underbust plus 4 inches", the two approaches can give different numbers for the same body.
How to Measure Correctly
Use a soft measuring tape. Wear a non-padded bra or no bra for accuracy.
| Step | How to Measure | Result |
|---|---|---|
| 1. Underbust | Wrap tape directly under bust, snug and level | Your band size base |
| 2. Bust | Wrap tape at fullest point of bust, relaxed, not tight | Used for cup calculation |
| 3. Calculate | Subtract the band size from the bust | Difference = cup size |
Worked example. Underbust 33.5 in and bust 38 in. The underbust rounds to 34, which is even, so the band is 34. The difference is 38 − 34 = 4 inches, cup D: a 34D in the UK and US, 75D in the EU, 90D in France and 12D in Australia. In centimeters the same person measures about 85 cm and 96.5 cm.
Which band method we use
We use the underbust measurement itself, rounded to the nearest inch and up to an even number, because that is what most UK fitters and many US brands use today. Older US charts add 4 or 5 inches to the underbust (the "plus four" method), which gives a bigger band and a smaller cup, for example 36B instead of 32D. If a brand's own chart uses that method, follow the brand.
Checking the fit
A calculator gives a starting size. In the fitting room: the band should sit level and snug on the loosest hook, the center front should lie flat against your breastbone, and the cups should hold all breast tissue without gaping or spilling. If the band rides up, go down a band and up a cup; if it digs in, try the sister size above. Sizing differs between brands and styles.
Breast size can change with weight, pregnancy, breastfeeding, the menstrual cycle and age, so re-measure every so often. See a doctor about a new lump, skin dimpling, nipple changes or pain in one breast, whatever your bra size.