32D vs. 34D vs. 36D: Same Cup Letter, Different Cup Size!

Have you ever wondered why a 32D, 34D and 36D don't fit the same, even though they all have a D cup?

Today, we're talking bra sizing! And more specifically, one of the biggest misconceptions we come across when fitting customers.

A D cup is a D cup, right? Well, not exactly!

One of the things we explain to customers all the time is that a 32D, 34D and 36D are not the same size in the cup. Even though they all have the same cup letter, the actual cup volume increases as the band size increases.

Let's break it down!

So, What's the Difference?

The secret is that bra cup sizes are proportional to the band size, rather than being a fixed measurement.

As the band size increases, the cup volume associated with the same letter generally increases, too.

For example:

• 32D: Smaller band, smaller cup volume.
• 34D: Slightly larger band and more cup volume than a 32D.
• 36D: Larger band and more cup volume than a 34D.

Although all three bras have a D cup, they are designed for different proportions. A 36D has a larger overall circumference and more cup volume than a 34D, which has more cup volume than a 32D.

Think of the cup letter as only half of your bra size. The band number matters just as much!

But Wait, What If You Want the Same Cup Volume?

This is where sister sizing comes in.

Sister sizes are bra sizes that have approximately the same cup volume but different band sizes. When you change the band size, you also change the cup letter to keep the cup volume roughly equivalent.

For example:

Moving up one band size generally means moving down one cup letter to maintain approximately the same cup volume. Moving down one band size generally means moving up one cup letter.

So, 32DD, 34D and 36C are commonly considered sister sizes.

Keep in mind that sister sizes are a starting point. The shape and construction of the bra, as well as the fit of the band and cups, can affect which size works best.

Why Does This Matter?

We see this quite often when customers come in wearing a bra with a band that's too loose.

For example, someone might be wearing a 36D because the cups seem to fit, but the band is riding up her back. The band is too loose to provide the support she needs.

Sometimes, a smaller band with a different cup size will give her a much better fit.

Remember, the band plays a major role in supporting your breasts. If it's too loose, the bra can shift around, the straps may slip, and you may find yourself constantly adjusting it throughout the day.

And nobody wants that!

Does This Mean You Should Always Wear Your Sister Size?

Not necessarily!

Sister sizing is a useful tool, but it doesn't automatically mean the sister size will fit you better.

The band should feel secure and comfortable, the cups should contain your breast tissue without cutting in or gaping, and the centre of the bra should sit properly against your chest when the style is designed to do so.

The brand and style also matter. A moulded T-shirt bra can fit very differently from a seamed lace bra, even in the same size.

That's why we always look at the whole picture when fitting a customer.

Let All Figure Help You Find Your Fit

Your bra size is a starting point, not the whole answer. Understanding the relationship between band and cup size is a great first step, but the best bra is the one that fits your body comfortably and provides the support you need.

If you're unsure whether you need a 32D, 34D, 36D or a sister size, we're here to help.

Explore our Fitting Guide or book a bra fitting with All Figure. We'll help you find a size and style that works for you.

Happy bra fitting!

Signing off until next time! x