D vs DD, 34D Cup, 34DD Cup, and 34DDD Bra Cup Sizes

D is one of the most confusing bra cup sizes because it includes both double and triple cup letters, all of which are of slightly different sizes. These sizes vary even more between different international sizing systems, so choosing the right 34D Bra, 34DD, or 34DDD bra cup size is anything but simple.

Determining whether you should be wearing a size 34 bra band is relatively easy. If the circumference of your ribcage just below your breast measures between thirty-two and thirty-four inches, then a 34 band size is probably your best fit. When measuring your band size, remember always to round up the number you measure to the next highest even number (i.e., 32.5 automatically rounds up to 34). 

34D Bra Size - Panache Tango Balconnet Bra

Cup sizes are slightly more complicated. The US sizing system defines a D cup size as the size designed to fit women who have a four-inch difference between their band and bust measurements. A five-inch difference translates to a DD cup size, and a six-inch difference translates to a DDD.

In the US, a DD cup size is equivalent to an E. The majority of mainstream US lingerie brands use DD, so it’s relatively rare to come across an E bra size. However, if you come across two US lingerie brands that label their cup sizes differently, it is helpful to remember that DD and E are technically the same cup size.

The case of DDD and F cup sizes follows this same pattern. According to the US sizing system, both DDD and F sizes translate to a six-inch difference between your bust and band measurements.

If your measurement difference is somewhere in between four inches and five inches or between five inches and six inches, you should look into sister sizes for 34D, 34DD, or 34DDD cup sizes. Sister sizes are bra sizes with the same cup volume but slightly different band sizes, which allows them to offer a better fit for women who are in between sizes. 34D’s sister sizes are 32DD and 36C; 34DD’s sister sizes are 32DDD and 36D, and 34DDD’s sister sizes are 32G and 36DD.

Different parts of the world follow different sizing systems for bra sizes. If you’re buying a bra that is sized according to an international sizing system, your band size will likely stay the same, but your cup letter will probably change. In Europe’s EU sizing system, DD and DDD cup sizes don’t exist. This sizing system only uses E and F for these sizes, instead. In the UK sizing system, D and DD are equivalent to US sizes. A US DDD size, however, translates to an E in the UK, which is especially confusing since DD and E are the same cup size in the US.

Best Bra for 34D, D, and DDD Cup Size

There is no absolute best bra for a 34D, 34DD, and 34DDD cup size. There is a widespread misconception that wearing a D, DD, or DDD bra size severely limits the types of bras that you can wear comfortably. While it is true that women with larger busts require a more considerable amount of support than women with smaller breasts, that doesn’t mean that your bra size should dictate which bra styles you can and can’t wear.

Most women who wear a D cup or higher have higher expectations for their bras and hold them to a higher standard than women with an A or B cup size do. Wearing a bra that doesn’t adequately support your bust can lead to extreme discomfort and even severe chronic pain, so it’s no wonder larger-busted women tend to take their bra choices more seriously.

If you have a D, DD, and DDD cup sizes, don’t write off specific bra styles just because you don’t think they will be able to offer enough support. A bra of any style can fit large breasts as long as it is designed with comfort, support, and security you need. 

34D, DD, DDD Push Up Bra

You don’t have to have small breasts to rock a push-up bra. Many women with larger breasts prefer to wear push up bras to enhance their cleavage and offer extra shaping and lift.

If you’re looking for a supportive push-up bra to fit your 34D, 34DD, or 34DDD bust size, look for styles that are designed extra support features. Push up bras in cup sizes D and above should feature underwire, adjustable straps, all-over lining, and a full band to provide a comfortable, secure fit for larger-busted women.

34D, D, DDD Sports Bra

Support is essential in every bra, but it is especially vital in sports bras designed for women with a D cup size or higher. Never settle for a sports bra that offers inadequate support.

Sports bras designed to fit 34D, 34DD, and 34DDD cup sizes should feature underwire; molded, sectioned cups; breathable material; and wide, padded straps to minimize bouncing and discomfort while you work out.

34D, DD, DDD Bralette

Bralettes are notorious for being targeted toward women with petite breasts. The vast majority of bralettes offer little to no support. Few include wire, and many styles are made from a single layer of flimsy fabric, lace or mesh.

Don’t give up on bralettes, yet, though. Bralettes that are designed for larger-busted women do exist; they are just much less common than styles for women with an A or B cup. Hold out for supportive bralette styles that include real cups, a solid band, lining, and adjustable straps.

34D, DD, DDD Good Posture Bra

Good posture bras are trendy among full-busted women. The weight of large breasts can impair your posture over time, and good posture bras are designed specifically to correct this problem.

These posture-correcting bras are usually designed with a racerback style that features a unique criss-cross pattern across the back. This design allows good posture bras to comfortably guide your shoulders and spine into proper alignment to improve your posture and reduce strain on your back and shoulders.