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👙 RU Bra Size to US Bra Size Converter

Free online tool to convert RU 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

75C RU = 34C US

RU Bra Size to US Bra Size Conversion Table

RU SizeUS Size
65A RU30A US
65B RU30B US
65C RU30C US
65D RU30D US
65E RU30DD US
65F RU30DDD US
70A RU32A US
70B RU32B US
70C RU32C US
70D RU32D US
70E RU32DD US
70F RU32DDD US
75A RU34A US
75B RU34B US
75C RU34C US
75D RU34D US
75E RU34DD US
75F RU34DDD US
80A RU36A US
80B RU36B US
80C RU36C US
80D RU36D US
80E RU36DD US
80F RU36DDD 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 RU Bra Size to US Bra Size Conversions

Converting bra sizes from RU to US requires converting both the band number and the cup letter. Enter your size above to get the correct US equivalent with cup conversion included.

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.

For reference: this page provides a RU-to-US conversion table covering common values, the exact mathematical formula, and frequently asked questions.

Frequently Asked Questions

How do I convert RU 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 RU Bra Size?

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

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

The size relationship between RU 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 RU 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.

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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.