34DD Bra Size Guide

What is a 34DD bra?

In cup and band bra sizing, the number refers to your band size, which is essentially the circumference of your ribcage. The letter actually refers to the difference in size between your band and bust measurement. A DD cup means there’s a 5 inch difference between your band measurement and your bust measurement. 

While it’s common for people to over-identify with a certain cup size, the reality is that your cup size is just as much based on your band size as it is your bust size. That means that as your body fluctuates, either monthly or over the course of your life, your cup size can fluctuate too. You may also be different cup sizes from brand to brand as bra sizing can vary across different companies.

Proper bra fit for a 34DD bra

Great fit

• The band of the bra is level all the way around your body

• Your breasts fill the cup without spilling over

• The straps should stay on your shoulders without digging in

• The center of the bra lays flat against your chest between your breasts

Too big

• Your breasts don’t fill the cups

• You don’t feel secure or supported

• Your straps fall off your shoulders

Too small

• Your breasts spill out over the cups

• You can feel underwire pinching your skin

• You see red marks on your skin after you take your bra off

Sister sizes for a 34DD bra size

Bra sizing uses something called "sister sizing," where different bras can have the same cup volume but different band/cup combinations. For a 34DD, the sister sizes would be 32DDD/E (smaller band, larger cup letter) and 36D (larger band, smaller cup letter).

The cup volume of a 34DD matches these sister sizes, but the fit is quite different because of the band. When you look at different band sizes with the same cup letter, a 34DD has less volume than a 38DD but more volume than a 30DD.

Sister sizing comes in handy when a bra is almost right. For example, if the cups of a 34DD fit well but the band feels too tight, you might try a 36D instead. If the band is too loose but the cups are perfect, a 32DDD/E could work better. This works best when you only go one band size up or down; more than that and the proportions get too different.

Choosing the right 34DD bra

When it comes to choosing the right 34DD bra, fit is everything. Use our bra size calculator to find your perfect bra fit with just a click. Next, you’ll need to decide if you prefer an adjustable bra style or a hardware-free, pull-over bra style. 

CrossOver Bra

Mesh details add a signature touch to this best-selling, wireless bra. Adjustable straps and a hook and eye closure let you customize your fit. Because the CrossOver Bra is adjustable, it’s a great match for a 34DD bra size, which has a relatively small band size and relatively large cup volume. 

Silhouette Bra

Flat, stretch silicone is coated in soft velvetine flocking to provide structure and style to this wireless bra. Adjustable straps and a hook and eye closure let you customize your fit. Once again, this bra’s adjustability and stretchy cups are a great match for a 34DD bra size.

SoftForm Bra

The SoftForm Bra is the ultimate wireless smoothing bra. Made with wide, thick straps that lay gently against the skin and a seam-free design that disappears under clothing, this bra is the go-to for comfort and support. The bra’s supportive straps and full coverage cut make this style an excellent match for a 34DD bra size, as these features are designed to support a heavier chest.

CloudEmbrace Bra

This cup and band style bra features molded memory foam cups that lift and shape like a traditional t-shirt bra. CloudFuse honeycomb bonding on the wings provides back and side smoothing. Adjust the straps and band for a perfect fit. A 34DD bra size will enjoy this style because of its cup and band sizing, which is tailor-made to each specific bra size.

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