👙 US Bra Size to UK Bra Size Converter
Free online tool to convert US bra sizes to UK. Enter your band and cup size for an instant, accurate result — band and cup both converted.
Result
34C
34C US = 34C UK
US Bra Size to UK Bra Size Conversion Table
| US Size | UK Size |
|---|---|
| 30A US | 30A UK |
| 30B US | 30B UK |
| 30C US | 30C UK |
| 30D US | 30D UK |
| 30DD US | 30DD UK |
| 30DDD US | 30E UK |
| 32A US | 32A UK |
| 32B US | 32B UK |
| 32C US | 32C UK |
| 32D US | 32D UK |
| 32DD US | 32DD UK |
| 32DDD US | 32E UK |
| 34A US | 34A UK |
| 34B US | 34B UK |
| 34C US | 34C UK |
| 34D US | 34D UK |
| 34DD US | 34DD UK |
| 34DDD US | 34E UK |
| 36A US | 36A UK |
| 36B US | 36B UK |
| 36C US | 36C UK |
| 36D US | 36D UK |
| 36DD US | 36DD UK |
| 36DDD US | 36E UK |
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 US Bra Size to UK Bra Size Conversions
This free US to UK bra size converter handles both band and cup sizes accurately — including the differences between US DDD, UK E, and EU F at the larger end of the scale. Select your band and cup below for an instant result.
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.
Below you will find a pre-calculated conversion table, the exact formula used, and answers to common questions about US Bra Size to UK Bra Size conversions. All calculations follow internationally recognized standards.
Frequently Asked Questions
How do I convert US Bra Size to UK 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 UK Bra Size are in 1 US Bra Size?
The relationship between US Bra Size and UK Bra Size is non-linear. Use the calculator above or the reference table on this page for specific values.
Is US Bra Size larger or smaller than UK Bra Size?
The size relationship between US Bra Size and UK Bra Size depends on the input value because this conversion is non-linear (reciprocal).
When would I use UK Bra Size instead of US Bra Size?
Use UK sizing when shopping brands that label their products in the UK 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.