As if bra sizing wasn’t complicated enough with one system of sizing. International systems of bra sizing, or sizing by country can be even more difficult. The systems don’t translate cleanly, but we can make approximations. Currently, there are 6 different international systems of bra sizing still in use. First things first, let’s take a look at band sizing conversions:

Band Sizing and International Conversion

We see lots of trouble in band sizing between US brands, so converting between international systems and then by brand sounds daunting. But keep in mind, this is just to give you a starting point. This way, buying bras in other sizing systems won’t be a complete shot in the dark. Check out the first sizing chart here.

Not so bad, right? This conversion should be pretty straight forward and clean in the results it yields. The cup sizing portion next may be a bit more scary…

Cup Sizing and International Conversion

The methods of cup sizing between systems can be quite fickle, and much more frustrating to decipher than the band size conversion. This frustration is in thanks to the fact that they do not go up or down on the same scale as each other. Some sizes will be in between others. If you are familiar with inch to centimeter conversions (1 in = 2.54 cm) then this will help in the rationalization of cup size conversion. See the second chart here.

To break it down a little, cup sizing for each different system falls into one of two sizing methods: increasing cup size every inch (US and UK), or increasing cup size for every two centimeters (everyone else). This is pretty straight forward, right? Since one inch does not equal two centimeters, but, rather, 2.54 centimeters, like I mentioned above, there is a bit of an uneven conversion between the two sizing methods. This sizing discrepancy becomes increasingly more exaggerated as cup sizes go up in size.

UK and US

The United Kingdom band sizing system utilizes methods that correspond to chest circumference. The measurements used in this system are in inches. For example, if you have a chest circumference of 34 inches, then you have a band size of 34. UK cup sizes use the one inch method. Every one inch difference between chest circumference and bust circumference, the cup size increases one size.

The United States also uses a system that is based on chest circumference. Don’t be fooled, the cup sizing and labeling of US sizes is much different. Up to a 16 inch difference can be found between US and UK sizes when compared side by side. Because the discrepancy can be so dramatic, take precautions when purchasing from manufacturers who size differently.


As with any sizing system, there will be plenty of frustrating variation in size between brands. Add in the difference in elasticity and wear factors of a variety of fabrics… If you’re looking to try a new brand, and can only find it online, take a look at reviews on bra blogs and other bra info sources before you buy.

In EU sizing, cups increase by 2 cm for every band size. The Japanese labeling system has measurements beginning with cup size listed before band size, such as B70 as opposed to 70B.
The method of band sizing in Europe and Japan (EU system of measurement) does not correspond to under bust circumference. An easy way to find to find your rough EU band size goes like this:  round your under bust measurement to the nearest 5  band sizes increase in multiples of 5 centimeters, such as 55, 60, 65, 70, …), and subtract 10.


Australia and New Zealand (AUS) sizing method is quite similar to the UK method and based on the same idea. The major difference is that band size is measured by dress size. These dress sizes are only based on women with B and C cups. This bias leads to horrendous inaccuracies. Basing bra size on dress size just doesn’t work for many of us. Circumference of chest is used in the basis of dress size, and this does not translate information regarding breast size and shape very well.


BEF is the system used in Belgium, Spain, and France. This system is comparable to the European and Japanese system. The minor conversion factor is that the band size label is exactly 15 larger than EU’s. An EU band of 60 would be equivalent to a BEF 75 band.


The following chart is not a conversion chart. The purpose of the chart is to display the labeling differences. Though the conversions seem to be messy, the cup sizing of either particular system will increase in a friendly and linear way.

Online Conversion Charts

Online conversion charts can be handy in giving you a great starting place for your international size. A good web site is here. That web site has an easy to read chart that includes both band and cup size. Also, there’s a section for converting panty sizes, and general international sizes.

My Best Shopping Advice

Do any of the following symptoms make you think of your bra? Yes? Then it isn’t a good fit and it should be returned/replaced ASAP. If you experience discomfort under the band, soreness, underfilling the cups, spilling over the cups, or restricted movement, you’re bra doesn’t fit correctly.

When trying on a new bra, make sure to do the following:

  1. The band should be firm and snug around your body, but comfortable to wear. Standing side-on at a mirror, the band should be horizontal and should not be creeping or pulling up your back.
  2. There should be absolutely no poking, rubbing, or digging anywhere. The underwire at the front should lie flat against your rib cage. If they stick up or out funny, they’re the wrong shape for your body and breasts.
  3. Each cup should completely encompass each breast. There should be a smooth line where the breast and the top of the cup meet. Even if you are wearing a low cut style or balconette, there should be no ridge or spillage over the top of the cup.

With this in mind, you ca know that you are working with a correctly sized garment. That should make some conversions and online purchases a little easier!

If you enjoyed this article, then we're probably very similar. I'm Victoria Melo, and I know what it’s like to be busty and struggle finding the perfect bra. Not long ago, I was just another girl wearing the wrong bra size. When I finally discovered my real size and found great bras for my busty figure, it felt like a miracle. Now, I'm a bra fitter helping hundreds of women like you find their own miracle. Click here to read my lists of my favorite bras for you.
Nice to see you again. Would you like to get expert help to create your own Bustiest plan?YES, PLEASE!

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