Sizing systems are international systems for labeling bra size. There are six systems in use and even though measurements between the systems don’t exactly correspond, you can draw approximations. The system used depends on the brand of the bra, not the location you are purchasing it from.
The best way to measure band size is to stretch the bra and place the measuring tape parallel to it.
The 6 Bra Sizing Systems
UK Sizing System
- Band size is in measured in inches.
- Band size is in even numbers i.e. 28, 30, 32, 34, 36 etc.
- Cup sizes go from AA to L.
- From this post on bra size, you could tell that each additional cup size represents an additional 1 inch difference between the bust and underbust measurements.
US Sizing System
- Band size is measured in inches.
- Band size is in even numbers i.e. 28, 30, 32, 34 etc
- Unlike the UK system, cup size progresses as follows AA, A, B, C, D, DD, DDD/F, G, H, I, J, K, L, M, N
- After DD the measurements differ from the UK system.
EU and Japan (EU/JAP) Sizing Systems
- Band sizes are measured in centimeters.
- To calculate your band size, measure your underbust in centimeters, round it to the nearest 5 and subtract 10.
- Band sizes increase by 5 i.e. 50, 55, 60, 65, 70 etc
- Cup sizes increase by 2 cm, unlike the US/UK which increase by 1 inch.
- Cup sizes progress as follows A, B, C, D, E, F, G, H, I, J
- Note that the only difference between the EU and Japan system is that Japan places cup size before band size e.g. C65 instead of 65C.
Australia and New Zealand (AUS/NZ) Sizing System
- Band size is measured in inches (even numbers).
- Band size is based on dress size e.g. 8, 10, 12, 14 etc. However, these sizes are based on women with B and C cups.
- To calculate band size subtract 22 from the measurement e.g. UK 32 – 22 = AUS/NZ 10.
- Cup sizes progress as follows AA, A, B, C, D, E, F, G
Belgium, Spain and France (BEF) Sizing System
- Similar to the EU/JAP system in all aspects but band size. Add exactly 15 to your EU measurement to get your BEF size e.g. EU/JAP 55 + 15 = BEF 70
Italian and Czech Republic (I/CZ) Sizing System
- Band sizes begin at 0 for the EU/JAP size of 60.
As always, I would advise you to fit, swoop and scoop to find your perfect bra. The proof is in the fitting.
Bratabase has a great bra conversion calculator that lets you count ‘cups up.’ Don’t worry “cups up” isn’t an official term. Basically, when converting between US and UK, count the number of cups above DD you are, since the two systems are the same up to that point. Bratabase lists sizes based on how many cups into the progression it is (with UK AA = 0, A = 1, B = 2 etc.), without identifying it as a letter, since so many systems use different letters.
For example, I measure as a UK 32FF. FF is the 8th cup size in UK progression (A, B, C, D, DD, E), so on Bratabase, I would click on the 32:8 cell to look for bras in my size, and from there I would go to the brands I’m interested in and it will show me what size I would need in that brand.
Phew, that was quite the explanation, I hope it made sense. Basically Bratabase is a God send.