Apex Conversion

👙 UK Bra Size to US Bra Size Converter

Free online tool to convert UK bra sizes to US. Enter your band and cup size for an instant, accurate result — band and cup both converted.

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Result

34C

34C UK = 34C US

UK Bra Size to US Bra Size Conversion Table

UK SizeUS Size
30A UK30A US
30B UK30B US
30C UK30C US
30D UK30D US
30DD UK30DD US
30E UK30DDD US
32A UK32A US
32B UK32B US
32C UK32C US
32D UK32D US
32DD UK32DD US
32E UK32DDD US
34A UK34A US
34B UK34B US
34C UK34C US
34D UK34D US
34DD UK34DD US
34E UK34DDD US
36A UK36A US
36B UK36B US
36C UK36C US
36D UK36D US
36DD UK36DD US
36E UK36DDD 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 UK Bra Size to US Bra Size Conversions

This free UK to US 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 UK Bra Size to US Bra Size conversions. All calculations follow internationally recognized standards.

Frequently Asked Questions

How do I convert UK 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 UK Bra Size?

The relationship between UK Bra Size and US Bra Size is non-linear. Use the calculator above or the reference table on this page for specific values.

Is UK Bra Size larger or smaller than US Bra Size?

The size relationship between UK 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 UK 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

US Bra Size → UK Bra SizeUnited States (US) → European (EU)European (EU) → United States (US)United States (US) → France (FR)European (EU) → France (FR)
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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.