Estimate your bra size from two measurements and convert it between US, UK, EU, French and Australian sizing.
Measure firmly under the bust (band) and around the fullest part of the bust. The band rounded to an even number is your band size, and each inch of difference is one cup size. Band 32 in, bust 37 in = a 5 in difference = 32 DD (US) / 32 DD (UK).
This calculator estimates your bra size from two measurements — the band (just under the bust) and the bust (at its fullest point) — in inches or centimetres. It gives your size in the US/Canada, UK, EU, France/Belgium/Spain and Australia/New Zealand systems and suggests sister sizes. A second tool converts a size you already know between regions.
Sizing is not standardised: the same label can fit differently between brands and styles, so use the result as a starting point and try on. Poorly fitted bras can cause discomfort, so a fitting by a trained professional is worthwhile. For other size conversions, see the Shoe Size Conversion.
The calculator follows the standard modern fitting method.
| Measurements | US size | UK size | EU size |
|---|---|---|---|
| Bust 37 in, band 32 in | 32 DD (E) | 32 DD | 70 E |
| Bust 36 in, band 34 in | 34 B | 34 B | 75 B |
| Bust 40 in, band 36 in | 36 D | 36 D | 80 D |
| Bust 92 cm, band 76 cm | 30 DDD (F) | 30 E | 65 F |
| US 34C converted | 34 C | 34 C | 75 C |
| Label | US / UK | EU (EN 13402) | FR / BE / ES | AU / NZ |
|---|---|---|---|---|
| XXS | 28 | 60 | 75 | 6 |
| XS | 30 | 65 | 80 | 8 |
| S | 32 | 70 | 85 | 10 |
| M | 34 | 75 | 90 | 12 |
| L | 36 | 80 | 95 | 14 |
| XL | 38 | 85 | 100 | 16 |
| XXL | 40 | 90 | 105 | 18 |
| 3XL | 42 | 95 | 110 | 20 |
| 4XL | 44 | 100 | 115 | 22 |
| 5XL | 46 | 105 | 120 | 24 |
| Difference (in) | US cup | UK / AU cup |
|---|---|---|
| under 1 | AA | AA |
| 1 | A | A |
| 2 | B | B |
| 3 | C | C |
| 4 | D | D |
| 5 | DD (E) | DD |
| 6 | DDD (F) | E |
| 7 | DDDD (G) | F |
| 8 | H | FF |
| 9 | I | G |
| 10 | J | GG |
Round your underbust to an even number for the band, then subtract it from your bust measurement: each inch of difference is a cup size (1 in = A, 2 = B, 3 = C and so on).
Measure snugly under the bust for the band and loosely around the fullest part of the bust. Use a soft tape measure and keep it level.
A size with the same cup volume but a different band — for example 34C, 32D and 36B are sister sizes.
No. Band numbers and cup letters differ between the US, UK, EU, France and Australia, though cup letters broadly align after DD. The converter shows each region.
They match up to DD. After that, the US uses DDD/F, G and H while the UK uses E, F, FF and G.
Sizing is not standardised, so brand, style and fabric all change the fit.
Every six to twelve months, and after weight changes, pregnancy or breastfeeding.
A band that rides up or digs in, straps that slip or dig, cups that gap or overflow, and a centre panel that does not lie flat.
Either. The calculator converts automatically.
No. Everything runs in your browser.
