👙 AU Bra Size to US Bra Size Converter
Free online tool to convert AU bra sizes to US. Enter your band and cup size for an instant, accurate result — band and cup both converted.
Result
34C
12C AU = 34C US
AU Bra Size to US Bra Size Conversion Table
| AU Size | US Size |
|---|---|
| 8A AU | 30A US |
| 8B AU | 30B US |
| 8C AU | 30C US |
| 8D AU | 30D US |
| 8DD AU | 30DD US |
| 8E AU | 30DDD US |
| 10A AU | 32A US |
| 10B AU | 32B US |
| 10C AU | 32C US |
| 10D AU | 32D US |
| 10DD AU | 32DD US |
| 10E AU | 32DDD US |
| 12A AU | 34A US |
| 12B AU | 34B US |
| 12C AU | 34C US |
| 12D AU | 34D US |
| 12DD AU | 34DD US |
| 12E AU | 34DDD US |
| 14A AU | 36A US |
| 14B AU | 36B US |
| 14C AU | 36C US |
| 14D AU | 36D US |
| 14DD AU | 36DD US |
| 14E AU | 36DDD US |
Conversion Formula
Band conversion reference: US/UK: 28 30 32 34 36 38 40 42 44 EU: 60 65 70 75 80 85 90 95 100 FR: 75 80 85 90 95 100 105 110 115 AU: 6 8 10 12 14 16 18 20 22 JP/RU/KR: same as EU Cup conversion — canonical index (12 sizes, index 0–11): US: AA A B C D DD DDD G H I J K UK/AU/FR: AA A B C D DD E F FF G GG H EU/JP/RU/KR: AA A B C D E F G H I J K Common mistakes: US DDD ≠ UK DDD — US DDD = UK E US G ≠ EU G — US G = EU G (index 7 matches here) US DD = UK DD (same), but US DD = EU E (different)
About AU Bra Size to US Bra Size Conversions
The AU and US sizing systems use different band scales and diverge in cup notation above D cup. This converter handles the full size — band and cup — so you get an accurate result rather than just a band approximation.
This conversion uses a non-linear (reciprocal) relationship, so a simple multiplication factor does not apply. The formula section below explains the method, and the reference table shows common converted values.
This page includes a reference table of common AU Bra Size values pre-converted to US Bra Size, the conversion formula, and frequently asked questions. All values use internationally recognized conversion standards.
Frequently Asked Questions
How do I convert AU Bra Size to US Bra Size?
This conversion is non-linear. Use the calculator above for accurate results, or refer to the formula section on this page.
How many US Bra Size are in 1 AU Bra Size?
The relationship between AU Bra Size and US Bra Size is non-linear. Use the calculator above or the reference table on this page for specific values.
Is AU Bra Size larger or smaller than US Bra Size?
The size relationship between AU Bra Size and US Bra Size depends on the input value because this conversion is non-linear (reciprocal).
When would I use US Bra Size instead of AU Bra Size?
Use US sizing when shopping brands that label their products in the US system — for example, European luxury brands, UK high street stores, or Japanese lingerie retailers. Always verify sizing with the brand's own chart, as fit can vary by style and manufacturer even within the same system.
Why doesn't my cup letter stay the same when converting between systems?
Cup letters are only consistent up to D cup. From DD upward, the US uses DD, DDD, G, H, I while UK and AU use DD, E, F, FF, G, GG, H, and EU uses E, F, G, H, I. This means US 34DDD = UK 34E = EU 75F. The band number also changes because each system uses a different scale — US in even inches, EU and JP in 5 cm increments, FR adds 15 to the EU number, and AU uses garment numbers.
What is the most common conversion mistake with international bra sizes?
The most common mistakes are (1) keeping the cup letter unchanged when it should change — US DDD is NOT UK DDD, it is UK E; and (2) only converting the band while ignoring the cup. Both band and cup must be converted for an accurate size. A second common mistake is confusing EU and FR sizing: FR sizes are EU + 15 in the band but use the same cup letters.
Related Bra Size Conversions
All conversion results are provided for general informational purposes only. Our formulas use internationally recognized conversion factors; however, rounding may affect precision. Do not rely on these results for professional, medical, legal, or engineering decisions without independent verification. Read our full disclaimer.