12K Bra Size – Tailored Fit for Curvy Frames
Understanding 12K: What This Bra Size Really Means
A 12K bra size combines a band size of 12 (equivalent to a 34 in international terms) with a K cup, representing a fuller cup volume for those with a larger bust. It's an uncommon but essential size for curvy women with smaller frames and fuller busts who need solid support and a custom-like fit.
If you've ever struggled to find bras that don’t dig in, gape, or fall short on support, 12K could be your perfect match. And yes, this product size exists – and it deserves just as much comfort and style as any other.
International Bra Size Equivalents for 12K
| Region | Equivalent Size |
|---|---|
| Australia (AU) | 12K |
| UK | 34K |
| US | 34O |
| EU | 75O |
| France (FR) | 90O |
Quick Fitting Guide: Measure Your Bra Size at Home
All you need is a soft tape measure and a mirror. Here's how to get your fit just right:
- Step 1 – Band Size: Measure snugly under your bust (where your bra band sits). Ensure it’s level. Round to the nearest whole number. That’s your band size.
- Step 2 – Bust Measurement: Measure around the fullest part of your bust. Keep the tape relaxed but level.
- Step 3 – Cup Size: Subtract your band size from your bust measurement. Each inch difference equals one cup size.
Need help? Use our Bra Sizing Guide or visit us in-store for our expert bra-fitting service.
Sister Sizes & Fit Flexibility
Can’t find 12K? Try these sister sizes – they offer similar cup volume with a different band fit:
- 10KK – Tighter band, same cup volume
- 14JJ – Looser band, same cup volume
It’s all about balance – don’t be afraid to explore your options!
Best Bra Styles for 12K
When it comes to bras in 12K, structure and comfort are non-negotiable. We recommend:
- Lightly padded bras – Shape without bulk
- Wireless bras – Support without poking
- Seamless styles – Invisible under clothing
- Sports bras – Including the Women’s Non-Wired Sports Bra and No-Sweat Mesh Sports Bra Wirefree for active comfort
- Front-Close Sports Bra Wirefree – Effortless wear and ease
- Nursing bras – For mums wanting comfort and function
These styles deliver support, lift, and a flattering shape – whether you’re working, working out, or winding down.
Featured Brands That Stock 12K
At The Foundation, we celebrate every size – especially those that deserve more attention. You'll find 12K in styles from:
- Samanta – Elegant European craftsmanship and full-cup support. The Samanta Semi Soft is a standout for shape and comfort.
- PrimaDonna – Exceptional structure and all-day ease. Explore the Deauville and Madison collections.
- Elomi – Contemporary styles designed for fuller busts. Popular picks include Cate and Matilda.
We also offer swimwear for size 12K and support styles like Size Wonderwire. From summer holidays to day-to-day wear, we’ve got you covered.
Why Shop With Us?
- Lowest price guarantee on all full-priced bras
- Personalised customer service in-store and online
- Bras tailored to fit women with comfort, style, and support
Feel supported. Feel seen. Feel fabulous.
Explore our full range of 12K bras – crafted for your body size and lifestyle. Our collection is curated for daily wear, special occasions, and everything in between – all just a click away.
Frequently Asked Questions
What does 12K mean in bra sizes?
It refers to a band size of 12 (AU) and a cup size of K – ideal for fuller busts on smaller frames.
How do I know if 12K is my size?
Use a tape measure to check your underbust and bust measurements, then refer to our size chart.
Is 12K the same as 34K in the UK?
Yes – 12K (AU) generally corresponds to a UK 34K.
What bras do you stock in 12K?
We carry top-quality options from PrimaDonna, Elomi, and Samanta.
Can I return my bra if it doesn't fit?
Absolutely. Check our Orders & Returns policy for full details.
Need help choosing the right bra? Visit us in-store or get in touch.