We should start with some parameters to translate sizes as they vary from Europe to US

Bra Size Information A Note on Bra Cup Sizes There are enormous differences in cup size notation between manufacturers. This is especially true in sizes above D in the US, UK, AUS and NZ. In general, sizes between AA and DD are fairly standard but once we get above this there is little or no coherence. Some manufacturers use size DD but then continue with E, F, G, H, I, J, etc. Others use DDD to represent an E and some go on to use E, EE, F, FF, G, GG, H, HH, etc. This can make purchasing a large-cup bra difficult. European manufacturers tend to use a standard AA, A, B, C, D, E, F, G, H, ... scale thus avoiding the DD, DDD, EE confusion. In the interests of providing a standard scale, 85b.org has adopted a simple cup-size scale based on what is believed to be closest to a standard. For Imperial measurements (inches) cup sizes are expressed as AA, A, B, C, D, DD, E, F, G, H, I, J and K. You may need to check the corresponding size with the particular makers standards. It is clearly necessary for larger cup sizes to consult with the manufacturer and / or supplier to ensure the correct size. A Note on International Bra Sizing Differences Apart from the differences in cup size notation, there is another major possible difference in international bra sizes: US standard cup sizes tend to be calculated on half-inch boundaries whereas UK manufacurers tend to use one inch boundaries. For an explanation of this, please refer to the following table which shows a snapshot of UK and US bra cup sizes (A cup, B cup and C cup). Cup Size US UK A 0.6" - 1.5" 0.1" - 1.0" B 1.6" - 2.5" 1.1" - 2.0" C 2.6" - 3.5" 2.1" - 3.0" nb: measurements are expressed (in inches) as bust size minus adjusted band size(see Bra Size Measurement) It can be seen clearly from this that, if your measurements show a band / bust size difference of 1.5", your US cup size is A and your UK cup size is B. If your band / bust size difference is 2", your US and UK cup sizes are both B. This may not always be the case. Some manufacturers in the USA may determine their cup sizes on inch boundaries. International variance and equivelent sizes It is common for manufacturers of any country to attach size labels to their garments which quote their equivelent sizes in a number of different countries. Unfortunately, these are often inacurate. An example may help explain the problem. A bra made in Europe which corresponds to the european size 75B, for instance, will most probably be labelled as 34B (USA) and 34B (UK) and, as the method of calculation for cup size differ in these countries, it is possible that the physical size of the cup may differ also. In some cases the band size may also differ. In order to counteract this effect, the 85B Bra Size calculator calculates the results for each national standard seperately using the correct method for each. Try entering these measurements in their respective fields of the 85B Bra Size calculator: Band Size : 30 Bust Size : 36 Above Bust: 34 When you click on Calculate you may be surprised to see that, in this particular instance, the US and UK sizes are shown as 34B but the European size is 75C and not, as you may have expected, 75B. So what did the calculator do? It converted the inch measurements to centimeters and then calculated the European size according to standard EN 13402. At the same time it calculated the US size using the standard US method and the UK size with the method used in the UK. European clothes sizes follow the European Standard EN 13402. The 85B Bra Size calculator adheres to this standard. A General Note In general, it is always a good idea to have your bra size measured by a professional bra fitter and to try a bra on before purchasing and this is especially true for plus size bras. In this case, the results from our bra size calculator and converter should serve as a guide and a good starting point before actually trying and buying.