The science of bra sizes

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Panache Lingerie

Here at Panache we pride ourselves on the exceptional fit and comfort of our bras, as well as our trained fitters who have perfected our fitting guides over a number of years. But bra sizes can be a complete mystery: aside from trying to find exactly the right size, what do those letters and numbers actually mean?

You probably already know that the letter in your bra size refers to the size of cup, and the number refers to the band size. But how have we come to rely on that particular sizing system, and what are the ins and outs of the science of bra sizing?

The original methods of fitting a bra were thought in America during the early 1930s, with the ideas of lettered cup sizes being introduced in 1932. Originally, these letters referred to – rather unfortunately – the amount of sag that smaller and larger breast sizes had! Thankfully, we’ve kept the letters but changed the system so that now, these letters refer to the size of the breasts themselves. These original letters ranged simply from an A to a D cup, but as time has gone on more cup sizes have been added to provide a more accurate fit for a larger range of women.


bra size measurement

Band sizes, unlike cup sizes, didn’t really gain popularity in American until the 1940s, and it wasn’t until the fifties that the UK took up the American standard of bra measurement. Despite this, even now bra sizing varies wildly between manufacturers and different countries: getting hold of a properly fitting bra can be a difficult task.

Along with ensuring that you visit a professional fitter to make sure you know your own bra size, you can measure yourself and use our fit wizard to help you work out whether you are wearing the correct bra and the correct size. An important factor to remember – and something that not all women know – is that cup sizes are relative to band sizes. Sounds simple, but that means that a 32B and a 36B are significantly different and not just because of an extra 2 inches.

So how are the bra sizes calculated? Like the difference in contemporary manufacturers, there are a number of different fitting methods available and we always recommend speaking to a professional fitter for their advice. Essentially, two or three measurements are taken: one below the bust around your chest, and one around the fullest part of your bust. The difference in these measurements then determines the size of your cup, and the measurement from under your bust determines your band size.

Whatever size you are, it’s very important to get properly fitted with a bra that is comfortable and supportive. If you think you might be wearing the wrong size bra, why not take our Bra Fit Challenge for some helpful advice?

The science of bra sizes