34C Bra Size Guide

What is a 34C 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 C cup means there’s a 3 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 34C 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

How do you know if you're a 34C?

Finding your true size means taking accurate measurements with a soft measuring tape. It's pretty simple and takes just a few minutes.

For band size, measure directly underneath your bust, keeping the tape parallel to the ground. For cup size, measure around the fullest part of your bust while wearing a non-padded bra. Input each of these measurements into our bra size calculator to get your bra size.

If your measurements point to 34C, try several bras in this size to check the fit, as sizing varies between styles and brands.

Sister Sizes and When to Use Them

Sister sizes share similar cup volume but distribute it differently across band sizes. For a 34C, your sister sizes are 32D (smaller band, larger cup) and 36B (larger band, smaller cup).

These alternatives come in handy when your standard size doesn't feel quite right. A 32D offers more support through a snugger band, which is great if you find 34 bands stretch out quickly or if you like firmer support. A 36B gives more breathing room in the band while maintaining similar cup volume. This is perfect for comfort on bloated days or if you're between sizes.

Sister sizes also help navigate differences between brands. Some manufacturers run small or large, making sister sizing helpful for finding your perfect fit across different labels.

You might want to keep multiple sister sizes in your collection to handle natural body fluctuations throughout your cycle or for different activities. For example, you might reach for a tighter band for high-impact movement, or looser bands for lounging.

Choosing the right 34C bra

When it comes to choosing the right 34C 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, which is essential for a 34C bra size.

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. 

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. 

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 34C bra size will enjoy this style because of its cup and band sizing, which is tailor-made to each specific bra size.

Now that you understand your 34C size and what makes a great fit, we're here to help you find bras that work for you. Our wireless designs lift and support without underwire, so you get comfort that lasts all day. We've tested every style to make sure it fits just right.