DD Cup Bra Sizes DD-mystified (2024)

When is a DD cup bra not a DD cup bra? Well… all the time really!

The first thing to realise is that a “DD cup” doesn’t really mean anything without the band size paired with it. For example, a 30DD is not only smaller than a 38DD in the measurement around the band, but also in the capacity of the cup – there is no such thing as a “DD” size in itself.

This concept is best explained using the system of “sister sizes” – which you can find out more in depth in our guide to bra sister sizes. All of these bras are “DD” sizes for example – from 30DD to 38DD, each with a different band length and cup volume.

DD Cup Bra Sizes DD-mystified (1)

To find out the best size for you if you already have a bra that is fitting relatively well, our fitting guide has step by step instructions of what to look for in a well-fitting bra, and which steps to take to improve it. Starting at the beginning? How to measure bra size has you covered.

If you’d like to know why it’s so important to be sure which system you’re using to take your underband sizing, what makes DD+ brands different from “core size” ones, and understand more about DD+ as a size category in general – this guide is for you!

What is the difference between DD+ sizes and A-D sizes?

Roughly speaking, once the difference between the measurement around your ribcage and the measurement around the fullest part of your bust is more than 5 inches, a DD+ size is likely to be a good fit for you.

Bras designed for this size segment often use firmer underwires, more pattern pieces in the bra cups themselves, and sturdier fabrics and components, to provide more support and a more comfortable fit for a larger bust.

DD Cup Bra Sizes DD-mystified (2)

The difference in DD+ and below D band sizing systems, and why that matters

An important consideration if you’re already wearing a DD bra size of any kind and looking to shop for more, is what sizing system your current brand has been using. There are two different ways of sizing the band of bras (+4, and +0) and that can make a big difference as to which size you end up in.

As DD+ sizes have risen in popularity, many bra companies making the “core” sizes of A-D cups have extended into DD cups as well. However, the core industry standard method of sizing bra bands (sometimes referred to as the “+4 method”) is not used by brands specialising in larger cup sizes, starting at DD and going up.

The +4 sizing method takes the measurement of around your ribcage, where your bra band sits, and adds 4 inches to it (and then rounds it up, if it’s an odd number). However DD+ specialists (like ourselves) will simply take the measurement as it is. For example, for a measurement of 30 inches, you may be used to wearing a 34 band bra using the +4 system. In DD+ specialist bras though, you would be wearing a 30 size band.

You can double check which system your current bras use by measuring yourself with a tape measure, or looking up their sizing guide online and seeing if they suggest adding 4 inches to the underband measurement. You can also get a rough idea by looking at the other sizes that brand makes – are they mostly below DD (so likely using +4) or above it?

Very importantly though, this will now mean your cup size totally changes as well. Our bra sister sizes guide covers this in more depth, but for quick reference you can use the chart below to find your new cup size if your band has changed. The golden rule is that every time your band size goes up, your cup size goes down, and vice versa.

28E30DD32D34C
28F30E32DD34D36C
28FF30F32E34DD36D38C
28G 30FF32F34E36DD38D40C
28GG30G32FF34F36E38DD40D
28H30GG32G34FF36F38E40DD
30H32GG34G36FF38F40E
32H34GG36G38FF40F
34H36GG38G40FF

If you’ve got any questions at all or would like to double check you’ve picked the right size, just drop us a note and we’ll be very happy to advise further.

DD Cup Bra Sizes DD-mystified (3)

30DD and 38DD bra sizes compared

Why choose a DD+ specialist bra if I can get one from brands carrying all sizes?

Well the great thing is, you can do either! If you find a bra you love and it’s in your size (don’t forget to double check whether the brand is using +4 or +0 band sizing) there’s so many more choices now than there used to be. Often brands starting at DD will incorporate more supportive features, or design aspects specifically for this segment - so if you've found yourself wanting a bit more secure fit, that might be a good option to explore.

The important thing is finding a bra that makes you feel amazing every time you put it on.

Double D? Is that different to DD?

If you’ve been in a store and heard the fitter refer to a “double D” bra size, that’s what a “DD” size is – we just say “double” instead of repeating the letter when we describe the sizing out loud. The same applies to any other double lettering for different sizes, like FF (double F) or GG (double G). If you’re interested in which letters are double and which aren’t, bra sizes explained covers the whole list.

Is D or DD cup bigger?

DD is one cup size larger than D. After the core cup sizes of A, B, C, D the alphabet continues as the sizes get larger, but with some sizes having double letters (such as DD or FF)

There’s no difference in the spacing between single and double letter sizes, a DD is one full size larger than D, just like E is one full size larger than DD.

What about DDD sizes?

DDD is most commonly used in the US, and converts to an E or F cup in UK sizes – one size up from DD.

Many larger cup bra brands use UK sizing, so it’s worth being familiar with how sizes convert. Our international size charts cover the differences at a glance.

Is DD cup size big? Or small?

All bra sizes are relative, so while a 38DD is indeed a bigger cup volume than a 30DD, it’s important to remember this is just the level many brands start at.

For a long time, especially when larger sizes were hard to find, DD cups were sold as being the largest possible, fuelling the myth of “DD” as some kind of giant sizing.

In fact, not only is it extremely common to wear some version of a DD cup, it’s also very common to be mis-sized into one due to that being the largest available option to purchase from some stores. If you found yourself in a new band size after the +4 exercise above and wound up a 32F after thinking you were a 36DD, you’re not alone!

With bra cup sizing going up to L, LL, or M, DD definitely isn’t anywhere near the largest cup volume available, especially from specialist retailers.

The most vital thing to remember though? It doesn’t matter. Bra sizes exist purely for the purpose of being able to identify one that fits the way you want it to, gives you the level of support you would like, and feels comfortable.

Changing size to improve the fit you get from your bra doesn’t change anything else. As you can see from the wildly different cup letter you would get from using either +4 or +0 sizing, the very definition of “DD cup” completely depends on where you’re shopping in the first place!

So here's to a whole new world of bra size options opening up to you, and don't forget our expert fitters are on hand to help with any other sizing questions you may have.

DD Cup Bra Sizes DD-mystified (2024)

FAQs

What is a DD cup equal to? ›

As an example, a DD is a cup that falls halfway between a D and an F, reflecting a five-inch difference between a woman's breast and under-bust measurements.

Are 36DD and 38D the same? ›

Let's say you wear a 36DD and the band is too small but the cups fit. In order to go up to a 38 band size you need to go down a cup size. You would want to try a D in the 38 band, or a 38D. The 36DD and the 38D are the same cup size, the only difference is the 38 band is bigger around then the 36 band.

Why does the DD bra size exist? ›

When retailers used to only offer 4 sizes initially (A, B, C, D) they added the DD when they realised women needed to include a larger size. Therefore it was often seen that A meant X-Small breasts, B meant Small, C Medium and D Large. So anyone larger would this would need a DD bra size.

Is the D cup too big? ›

Three inches is a C, and four is a D. A D cup is large enough to add four inches to the chest measurement. People think D cups are huge because about 80% of women are wearing the incorrect bra size. They are wearing a D despite actually being a G.

Is a 34DD the same as a 36D? ›

A little lingerie industry secret shared ….

For example, a 36D holds 710cc of breast tissue - the same as a 34DD, 32E and 30F. A 34B, on the other hand, holds 390cc of breast tissue – the same as a 32C, 30D, and 28DD.

What size is DD in breast implants? ›

What Are Breast Implant Sizes?
Cubic Centimetres (cc)Approximate Bra Cup SizeNotes
300 – 400 ccCVaries based on existing breast tissue
400 – 500 ccDVaries based on existing breast tissue
500 – 600 ccDD or EVaries based on existing breast tissue
600 – 700 ccDDD or FVaries based on existing breast tissue
6 more rows
Jul 27, 2024

What bra size is closest to 36DD? ›

SISTER SIZE CHARTS:
36 BAND SIZE
Current Bra SizeSister Size DOWNSister Size UP
36D34DD(E)38C
36DD(E)34DDD(F)38D
36DDD(F)34DDDD(G)38DD(E)
5 more rows

How big are D-size breasts? ›

Under the bust
D CUP34 D36 D
Bust measurement (in inches)36.6 - 37.438.6 - 39.4
Under the bust measurement (in inches)29 - 3031 - 32

How big are 38DD breasts? ›

38DD *roughly* indicates a 38" underbust and 43" bust (DD = 5 inch difference between underbust and bust measurements), however, bear in mind that 6 measurements are needed to calculate bra size as accurately as possible!

What is considered large breasts? ›

On the basis of published data and results from this study, it is recommended that patients with a cup size>or=D or a bra size>or=18 could be categorized as having large breasts, with all other patients considered average in size.

Should I go up a cup size or band size? ›

If you go down in the band size, you need to go up in the cup size to maintain the same cup volume. On the other hand, if you go up one band size, you should go down one cup size. For example, if you wear a 36D, your sister sizes are 34E on the size down and 38C on the up.

Is a triple D bigger than a double D? ›

However, it's important to remember that cup sizes are relative to the band size, so a 32D will have a different volume compared to a 38D. The DDD cup, also known as an F cup in some sizing systems, is even larger and offers more support for those with a fuller bust.

How heavy are D cup breasts? ›

How much do D-cup breasts weigh? D-cup breast tissue has an average weight of 3.06 lbs or 1.53 lbs per breast. Whilst this is the average, some D-cup sizes breasts can weigh up to 6.7 lbs (or 3.35 lbs per breast).

What is the largest breast size without surgery? ›

Annie Hawkins-Turner has the largest natural breasts in the world. Her bra size is 102 ZZZ.

Why do I have to keep pulling my bra down? ›

There are a few potential culprits which could be causing this problem, including: wearing the wrong band size - if the band is too large, the weight of your breasts can potentially pull the straps and eventually the back band up. straps that have been adjusted too tightly.

What is a DD equivalent to? ›

Cup Size Chart
DifferenceUS (United States)EU (European)
4”DD
5”DDE
6”DDD/FF/DDD
7”GG
12 more rows

Is DD the same as H? ›

In the United States cup sizes range from A to N. The cup sizes get larger as the letters go up in the alphabet. Size D is bigger than A, and H is bigger than D. Sizes are as follows: AAA, AA, A, B, C, D, DD, F, G, H, I, J, K, L, M, and N.

Is bra size G the same as DD? ›

This is because the letter "G" represents a larger cup size than the letter "DD." However, it is important to note that bra sizes can vary between brands and styles, so it is always best to try on different sizes to find the best fit. What is the difference between D and G bra size? About 5 inches around your breast.

Is DDD the same as G? ›

In American bra size, A DDD cup is also called an F cup, which sits just one size above a G cup. It means that they differ by just one inch. A seven-inch difference between bust and band is a DDD or F cup. Meanwhile, an eight-inch difference puts you at a G cup range.

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