Australian Bra Size Guide: Every Size Explained (With Conversion Charts)

Australian bra sizing is confusing enough on its own — then add international shopping from US, UK, or European brands and it becomes a genuine puzzle. A 10E in Australia isn't the same as a 10E in the UK. A US 34DD is not the same as an Australian 14DD. The differences are subtle but significant, and getting it wrong means wearing a bra that doesn't fit properly.

This guide covers every Australian bra size from 8AA to 22H, full conversion tables for US, UK, and EU sizing, specific explanations for commonly searched sizes like 10A, 10E, 14E, 16D, and 16E, plus sister sizing explained in plain terms.

How Australian Bra Sizing Works

Australian bra sizes have two components:

• Band size — a number (8, 10, 12, 14, 16, 18, 20, 22) representing the circumference around your ribcage, just under your bust
• Cup size — a letter (AA, A, B, C, D, DD, E, F, G, H...) representing the difference between your bust measurement and your band measurement

To find your size at home:

1. Underbust measurement: Measure firmly around your ribcage directly under your breasts (in cm). Round to the nearest even number — this is your band size. If the number is odd, try both the size below and above.
2. Overbust measurement: Measure loosely around the fullest part of your bust (in cm).
3. Cup calculation: Subtract underbust from overbust. Each 2 cm approximately equals one cup size.

Cup size differences (Australian standard)

How Australian Sizing Differs from US and UK

This is where most people get confused. Here are the key differences:

AU vs UK sizing

Australia and the UK use almost identical sizing — with one important difference: Australian cup letters skip from D to DD to E, while UK sizing goes D, DD, E, F, FF, G. This means:

• AU E = UK E (same size)
• AU F = UK F (same size)
• AU G = UK FF
• AU H = UK G

In terms of band numbers: AU and UK use the same band numbers (AU 10 = UK 10, AU 14 = UK 14, etc.).

AU vs US sizing

The US system is quite different in both band and cup:

• Bands: US adds 4–6 to the underbust measurement to get the band number. So AU 10 = US 30, AU 12 = US 32, AU 14 = US 34, AU 16 = US 36, AU 18 = US 38, AU 20 = US 40, AU 22 = US 44.
• Cups: AU/UK cups use DD and then E, F, G, H. US cups use DD, then DDD or E, then DDDD or F. The naming gets messy. Practically: AU/UK D = US D, AU/UK DD = US DD, AU/UK E = US DDD, AU/UK F = US DDDD.

AU vs EU sizing

European sizing (used by French, German, Italian brands) is completely different:

• Bands: EU bands are the underbust measurement in cm rounded up: AU 10 ≈ EU 65, AU 12 ≈ EU 70, AU 14 ≈ EU 75, AU 16 ≈ EU 80, AU 18 ≈ EU 85, AU 20 ≈ EU 90, AU 22 ≈ EU 95.
• Cups: EU cups generally match UK/AU letters for A–D, then diverge slightly at larger sizes.

Full Conversion Table: AU → US → UK → EU

Use this master reference table when shopping from international brands:

Commonly Searched Australian Bra Sizes Explained

10A Bra Size Australia

A 10A is one of the smallest mainstream Australian bra sizes. It features:

• Band: 10 — underbust approximately 63–67 cm
• Cup: A — approximately 10–12 cm difference between bust and underbust
• US equivalent: 30A
• UK equivalent: 30A
• EU equivalent: 65A

10A is relatively rare in mainstream stores — most department stores start at 10B or 12A. For 10A bras, specialist retailers like Brava Lingerie, Elle Macpherson, or online specialists like Bare Necessities carry this size. Alternatively, try a 30A from international brands.

Common fit issue: 10A wearers often end up in a 12AA or even a teen/training bra because mainstream stores don't stock their size. This is one reason proper sizing matters — the right band provides 80% of a bra's support.

10E Bra Size Australia

A 10E is a narrow back with a relatively full cup — a combination that's notoriously hard to find in mainstream stores.

• Band: 10 — underbust approximately 63–67 cm
• Cup: E — approximately 20–22 cm difference
• US equivalent: 30DDD (or 30E at some US brands)
• UK equivalent: 30E
• EU equivalent: 65F

Many women who are actually a 10E have been wearing a 14B or 12C because those are what's available — they've gone up in the band and down in the cup. This is a classic "common fit mistake." A properly fitted 10E will feel much more supportive than a larger band size with a smaller cup.

Where to find 10E in Australia: Brava Lingerie (Melbourne/Brisbane/online), Kaazoo (online), Bendon lingerie, Berlei. UK brands like Freya, Elomi, and Panache also make 30E sizes readily.

14E Bra Size Australia

A 14E is a very common size for Australian women but still tricky to find in some chain stores.

• Band: 14 — underbust approximately 78–82 cm
• Cup: E — approximately 20–22 cm difference
• US equivalent: 34DDD (or 34E)
• UK equivalent: 34E
• EU equivalent: 75F

14E is on the cusp of "extended sizing" — most Target and Kmart stores stop at 14DD or 16D. For 14E, try Big W, Myer's lingerie section, specialty lingerie boutiques, or online at Bras n Things, Berlei, or international brands in 34DDD/34E.

16D Bra Size Australia

A 16D is one of the most commonly available sizes in Australian stores — you'll find this in nearly every mass-market retailer.

• Band: 16 — underbust approximately 83–87 cm
• Cup: D — approximately 16–18 cm difference
• US equivalent: 36D
• UK equivalent: 36D
• EU equivalent: 80D

The 16D equivalent when shopping US brands is a 36D — same cup letter, different band number. Easy conversion. If you're buying from a UK brand, it's also a 36D. This is one of the "standard" sizes where most systems align well.

Sister sizes for 16D: 14DD (smaller band, larger cup, same volume), 18C (larger band, smaller cup, same volume).

16E Bra Size Australia — Conversion Guide

A 16E is a common size that becomes trickier when shopping from international brands due to cup letter differences.

• Band: 16 — underbust approximately 83–87 cm
• Cup: E — approximately 20–22 cm difference
• US equivalent: 36DDD (also written 36E at some US brands)
• UK equivalent: 36E
• EU equivalent: 80F

The 16E bra size conversion to US is 36DDD — this trips people up because many US brands skip from DD to DDDD without labelling 36DDD explicitly. Look for "36E" (which some progressive US brands now use), or "36 3D." UK brands (Freya, Curvy Kate, Elomi) use 36E, which is an exact match.

Sister sizes for 16E: 14F (same cup volume), 18DD (same cup volume).

Sister Sizing Explained

Sister sizing is one of the most practical bra fitting concepts to understand. The idea: the volume of a cup changes as the band size changes. This means different sizes can hold the same cup volume.

How sister sizing works

For every step you go up in band size, go down one cup letter — and vice versa. The cup volume stays the same:

When to use sister sizing:

• The band is too tight but the cup fits — try the next band up, one cup down
• The band is too loose but the cup fits — try the next band down, one cup up
• Your exact size isn't in stock — the sister size has the same cup volume and may fit nearly as well

Common Fit Problems and What They Mean

The band rides up at the back

The most common complaint — and it almost always means the band is too big. Try going down a band size (and up a cup size to maintain the volume). Remember: 80% of support comes from the band, not the straps.

The underwire sits on breast tissue

This usually means the cup is too small. Try going up a cup size while keeping the same band. If this doesn't help, you may need a different underwire shape (full cup vs balconette vs plunge cuts all sit differently).

The straps keep slipping

Slipping straps are usually a sign that the band is too big (you're relying on straps for support that the band should provide) or that the bra style doesn't suit your shoulder width. Try a smaller band size or a racerback style.

Quad-boob effect (cup cuts into tissue)

The cup is too small. Go up a cup size. You may need to go up two sizes if the effect is significant.

Gaping cups

The cup is too big — go down a cup size — or the style is wrong (a deep-plunge style won't work if you have a wider breast root). Try a fuller-coverage style in the same size first.

Shopping Tips for Australian Bra Buyers

Buying from US brands (Victoria's Secret, Wacoal, etc.)

Convert your AU band by keeping the same number concept but note US bands are approximately the same numbers now (AU 14 = US 34, AU 16 = US 36). Cups: AU D = US D, AU DD = US DD, but AU E = US DDD. Check the specific brand's size chart as some brands now use EU-style cup lettering (E, F, G) rather than US-style (DDD, DDDD).

Buying from UK brands (Freya, Curvy Kate, Fantasie, Panache)

UK cups align almost exactly with Australian cups up to F. Beyond that: AU G = UK FF, AU H = UK G. UK brands generally offer excellent range in "hard to find" sizes and are a great option for Australian women in 10E, 12G, or similar sizes.

Buying from EU brands (Simone Pérèle, Triumph, Marie Jo)

Use the EU band conversion: AU 14 = EU 75, AU 16 = EU 80, AU 18 = EU 85. Cups align with AU/UK up to D, then check the brand's specific chart.