18GG
18GG Bra Size Collection
Find Your Perfect Fit: Understanding the 18GG Bra Size
If you wear an 18GG bra size, you’re not alone—and you absolutely deserve bras that feel as good as they look. At The Foundation, we’re here to help you feel confident, supported, and stylish—every single day. With a focus on expertly curated premium brands and fit-first support, let’s break it down:
- Band Size 18 in Australian sizing corresponds to an underbust measurement of around 98–102 cm.
- GG Cup Size reflects a fuller bust, typically showing a difference of about 24–26 cm between bust and underbust measurements.
This size suits those with a fuller bust who need support without compromising on comfort or style. Whether you're after full coverage, high-impact support, or fashion-forward designs, we’ve got a bra to suit your lifestyle and preferences.
International Bra Size Conversion Chart
| Region | Band | Cup |
|---|---|---|
| Australia (AU) | 18 | GG |
| UK | 40 | GG |
| US | 40 | J |
| EU | 90 | J |
| France (FR) | 105 | J |
Quick Tape Measure Sizing Guide
- Measure your underbust (just beneath the bust, snugly). This gives you your band size.
- Measure your fullest bust (across the nipples). Subtract your band size from this number to estimate your cup size.
- Each 2 cm difference usually equals one cup size.
Need support? Use our bra fitting guide, try our virtual bra fitting service, or visit a store near you. Our friendly experts are always ready to help.
Sister Sizes & Fit Flexibility
Not all bras fit the same. If you’re between sizes or exploring different styles, consider trying these sister sizes:
- 16H – Same cup volume with a tighter band
- 20G – Same cup volume with a looser band
- Other H bras depending on preferred band feel
Sister sizing is especially useful for trying different styles such as strapless bras or sports bras tailored to low, medium, or high impact activities.
Best Bra Styles for 18GG
From daily wear to maternity must-haves, our favourite styles for 18GG include:
- Lightly Padded Bras – Smooth, natural shaping with added modesty
- Wireless Maternity & Nursing Bras – Comfortable and supportive, minus the wires
- Flexiwire Maternity & Nursing Bras – Flexible structure, supportive design
- Sleep Bras Maternity & Nursing – Ideal for overnight comfort
- Full Cup bras – All-day support with full coverage
- Sports Bras – Designed for low to high impact activity levels
We also stock plus-size bras, curvy bras, and fuller bust lingerie options to support you through every stage of life.
Top Brands Stocked in 18GG
Explore trusted lingerie brands known for their comfort, style, and technical design:
- Panache– A leadern full coverage and precision support
- Elomi– Designed specifically ifor plus-size bras and curvier silhouettes
- Fantasie– Everyday elegance with superior structure
Looking for maternity essentials? Explore favourites like the Show Off Peppercorn Nursing Bra, Easy Multifit Nursing Bras, and Hands-Free Pump Bras. We also offer Reusable Nursing Breast Pads, Breast Pumping Bras, and Maternity Underwear & Briefs.
Why Shop with The Foundation?
- Free shipping Australia-wide on orders over $150
- Free exchanges and easy 100 Day Returns
- Expert virtual bra fitting services for personalised support
- Special offers and free gifts during select promotions
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Shop Now to discover your perfect fit in our expertly curated 18GG collection.
FAQs
How do I know if 18GG is the right bra size for me?
Measure your band and bust using a tape measure, or visit us in-store. If your underbust is around 100 cm and your bust measures 24–26 cm more, 18GG is likely your perfect fit.
What’s the difference between 18GG and 18G?
The cup volume. A GG cup is one size fuller than a G cup, offering extra room and support.
Can I wear a 16H instead of an 18GG?
Yes, 16H is a sister size. It offers the same cup volume with a firmer band—ideal if you prefer a snug fit.
Which brands carry the best 18GG bras?
We recommend Panache, Elomi, and Fantasie for their reliable structure, stylish designs, and inclusive sizing.
Do you offer bras for nursing or maternity in this size?
Yes. Our 18GG range includes T-Shirt Maternity & Nursing Bras, Breast Pumping Bras, and Reusable Nursing Breast Pads.