Looking for bras in a true 12C? You're in the right place. At The Foundation, we understand that accurate bra sizing is about more than numbers—it’s about feeling confident, supported, and comfortable. Our curated 12C collection includes trusted international brands, handpicked for women who value quality, style, and proper fit. Whether you're exploring different bra size systems or want to understand how a conversion table works for global shopping, we're here to guide you.

Understanding the 12C Bra Size

A 12C in Australian sizing refers to:

Band size (12): An underbust measurement of approximately 70cm
Cup size (C): A bust size about 15cm more than the underbust, indicating moderate breast tissue volume

If your underbust is around 70cm and your bust is approximately 85cm, you’re likely a 12C. This makes it a popular fit for many women seeking balance in body size and support. Understanding your correct size ensures comfort and avoids pressure from the wrong fit.

International Bra Size Conversion Table

Region	Equivalent Size
UK	34C
US	34C
EU	75C
France (FR)	90C

Use this bra size conversion table to compare sizes from country to country. Visit our size chart for more detail.

How to Measure Your Bra Size with a Tape Measure

A well-fitting bra starts with the right measurements. Here’s how to use a measuring tape at home:

Underbust Measurement (Band Size):

Place the tape level and snug around your ribcage, just under the bust.
Round to the nearest whole number (e.g., 70cm = size 12). This determines your band size.

Overbust Measurement (Bust Size):

Measure around the fullest part of your bust without compressing the tissue.
Subtract the band size from the bust size. The difference reveals your cup size.

Bust Measurement Guide:

12C means approx. 70cm underbust and 85cm overbust
A 15cm difference = C cup size

Explore our chart for sizing guidance, a handy bra sizing reference.

Sister Sizes and Sizing Flexibility

Understanding sister sizing (also called alternate size) helps you adapt when your bra feels too tight or too loose:

10D – Same cup volume, tighter band
14B – Same cup volume, looser band

These options help ensure you always find the correct band size and cup comfort. Sister sizes offer flexibility as your body size and shape shift.

Recommended Bra Styles for 12C

Looking for both form and function? Here are bra style favourites that flatter and support the 12C:

Lightly padded bras – Shape-enhancing without bulk
Wireless bras – Ideal for lounge and light support
Seamless bras – Perfect under tees and slim silhouettes
Balconette bras – Lift and flatter the neckline
Full coverage styles – Support with comfort
Wider straps – Added comfort for all-day wear
Higher-support styles – Great for fuller busts or active wear

Explore what suits you best from our everyday underwear essentials range.

Shop Bras in 12C from Premium Brands

You’ll find 12C options from an extensive range of globally renowned brands:

Each brand in our collection is selected for quality, craftsmanship, and fit expertise. The brands range includes something for every taste, from minimalist to elegant.

Find Your Fit. Feel the Difference.

Whether you're after your everyday essentials or something for a special occasion, the right fit changes everything. Our 12C range is crafted to support your unique shape with confidence. Don’t forget to use our size and conversion tools to check how your size aligns globally.

Shop Now to discover bras that blend science, comfort, and style.

FAQs

What does a 12C bra size mean?

It means a band measurement of around 70cm and a bust measurement around 85cm—creating a 15cm difference that equals a C cup size. This is typical for a balanced bust-to-body ratio.

What are sister sizes for 12C?

Sister sizes include 10D (tighter band, same cup) and 14B (looser band, same cup volume). These sister sizes allow room for flexibility.

How do I measure correctly?

Use a tape measure: Measure under your bust for the band size, and around the fullest part of your bust for the cup size. Be sure the tape is flat and not twisted.

Where can I find an international size chart?

Right here or in our size chart, which includes an international bra size converter and helpful comparison.

Which styles are best for 12C?

Styles like lightly padded, seamless, and higher-support styles with wider straps are perfect for comfort, posture, and style.

Explore the 12C Collection – Because fit should never be a compromise.

12C Bra Size Collection