34DD in numbers
| Inches | Centimetres | |
|---|---|---|
| Underbust | 33–35 | 84–89 |
| Bust | About 39 | About 99 |
| Difference | 5 | 12.7 |
The five-inch difference is measured around the whole chest, not straight out in front, which is why a 34DD under clothes reads as a moderate bust.
Sizes with the same cup volume
A 34DD cup holds the same as a 32E, a 36D and a 38C. If you can picture a 36D or a 38C, you can picture the amount of breast tissue in a 34DD. The 34DD wearer simply has a slimmer ribcage. The details are on the 34DD sister sizes page.
Why two people in a 34DD look different
A size fixes two measurements. It leaves a great deal else open.
- Shape. The same volume can be narrow and standing well forward, or wide and close to the chest. The first looks fuller from the side, the second from the front.
- Where the fullness sits. Fuller above the nipple gives a rounder upper bust. Fuller below gives a gentler slope.
- Frame. On someone short with narrow shoulders, a 34DD is a noticeable bust. On someone tall and broad, it looks small.
- Tissue. Firm tissue sits higher. Softer tissue sits lower without a bra and changes more with the bra's shape.
- The bra. A moulded push-up, an unlined balconette and a minimiser give three different outlines to the same person.
The breast shapes guide explains these differences.
Why the popular image is wrong
"Double D" is used in everyday speech to mean a very large bust. The image attached to it usually belongs to a far bigger size on a smaller band, something like a 30G or 32GG, worn by someone who was never measured that way or described that way.
The reputation dates from a time when shops stopped at DD and sizing methods put most people in smaller letters. There is more on that in is DD a big cup size?
Are you really a 34DD?
It is a size many people wear when their real size is close by. A 34 band is a common default, and DD is where many ranges stop. If your 34DD band rides up, or the centre panel does not lie flat, try a 32E or 32F. If you have a ridge over the top of the cup, try a 34E. The signs that separate these are in DD cup vs E cup.
Frequently asked questions
What are the measurements of a 34DD?
An underbust of about 33 to 35 inches and a bust of about 39 inches. In centimetres, roughly 84 to 89 cm under the bust and 99 cm around it.
Is 34DD an average size?
It is one of the most commonly worn UK sizes. In a University of Portsmouth fitting study, 34DD was the size participants most often reported wearing.
What is a 34DD in other countries?
US 34DD, EU 75E, France 90E, Australia 12DD.
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