top of page

The Complicated World of Bra sizes

Why Bra Charts Don't Work

Bra sizing may appear simple to the untrained eye. Take the measurements. Do the math. Look up a size chart. And you’re all sorted! Phew! If only life were that simple! Bra sizes are way more complicated. Read on, for some ground-shattering myth-busting about your bra size. And if you are one of those who feel puzzled or are mystified when it comes to their bra size, worry not. You are not alone in this! Most of us continue to buy the same size year after year (which by the way, is a huge mistake) or solely rely on the advice of sales person. Awareness about this complicated process is the first step towards understanding what our breasts need.

Bra sizes are alphanumeric, just like our passwords

A bra size ALWAYS consists of a numerical component and an alphabet e.g. 36C, 32F, 85DD. The number represents the band size and the alphabet denotes the cup size.

Measurements and sizes are essentially different

Measurements are, what they take when you go to a lingerie boutique or to a tailor, circling your bust with their measuring tape, tightening it around your chest, telling you when to breathe, or more precisely, when not to breathe. And at the end of the whole frisking ordeal, mutter a number in inches or centimeters.

When we talk about size, please note that it is only a designation such as 32B or 85E. It is NOT an indication of you being big or small. Think of it as a filing system which helps your fitter locate what you need. Don’t obsess over these size designations and don’t be embarrassed. Own up your size!

The “underbust”, “overbust” and “above the bust” conundrum

Traditionally, to arrive at the bra size, two measurements are taken – one, immediately “under the bust” and the second, at the fullest part of the bust or “over the bust”. A few lingerie boutiques prefer to do it differently. Victoria’s secret, for example, takes an “above bust” measurement instead of “under the bust”.

Tape measure is overrated

The measuring tape only measures the circumference of your body, a 2-D measure (instead of 3-D) of your body rather than your breasts. – an oversimplified method. It does not account for the mass, the volume, the firmness, or the shape of your breast tissue.

We are working on a tool to help you find your perfect fit based on all these parameters. Register here to try out our tool for free when we launch it!

Your band size is NOT equal to the underbust measurement

Here’s the protocol followed to ascertain the band size :

1. Round off the under bust measurement (in inches) to the next even number.

2. Add 4 inches to the number

While, most US brands may instruct you to measure yourself under the bust but their band sizes actually refer to above bust. That is what the addition of 4 inches, is for. As a rule of thumb, the above bust measures 4inches more than the under bust.

Take a look at the examples highlighted on the size chart from La Senza below :

For example, if your measurement is 27.4in. then round it up to 28in. However, "28" is NOT your band size. As mentioned before, US bra band sizes refer to above bust measurements. Compensate for this by adding 4. This gives us: 28 + 4 = 32. The resulting US bra band size is 32.

Cup volume is NOT same across different band sizes

Cup sizes are generally denoted by a letter. Bra manufacturers and fitters all along have been using a formula to determine the cup size of their clients. Measure the fullest part of the bust and subtract the underbust measurement from it. This difference between the over bust and under bust gives the cup size.

First, the obvious: The cup volume increases as the cup size increases. This stands true, when comparing different cups across the same band size. Please note that cup size and cup volume are two entirely different parameters.

Now, for the not so obvious inferences : This size chart from Triumph would have you believe that the cup sizes work independently and that cup volumes remain conserved across all band sizes. Which is.. totally untrue!! A “B-cup” has no meaning unless cited with it’s band size. Cup volume of a 32B is not the same as 36B. And that’s because bra cups are designed on a band to bust ratio. The cup size is merely an indication of how large the cups are in relation to the band size. The cup volume for a given cup size increases as the band size increases.

Sister sizes: Key to trying the right sizes

This is the important part where we discuss how bra sizes actually work. Sister sizes are alternate bra sizes to the specific size calculated for you. These sizes have a different band size and cup size ( which are only size designations) but same cup volume. For example, the cup volume of 36D is same as the cup volume of 34E and that of 32F and so on.

What does it mean for you? A good understanding of sister sizes helps you make the right bra size choices for you. That is, when you change your band size, you need to change your cup size accordingly. As a rule of thumb, go up a cup size when you go down a band size and go down a cup size when you go down a band size. This rule helps you conserve the cup volume when moving up or down a band size.

I hope this article helps you understand how bra sizes work but if you still have questions, shoot away in the comments below , take our fit diagnosis quiz, or reach out to us

for a personalised fit session to help you find your perfect fit.

1,063 views0 comments


bottom of page