United Kingdom Size 30B to US: 30DD

United Kingdom Size 30B: Corresponds to a ribcage band of 76.2 $\text{cm}$ (30 $\text{in}$), bust volume cup size 30B, and recommended sister size 32A.

US: 30DD: Corresponds to a ribcage band of 76.2 $\text{cm}$ (30 $\text{in}$), bust volume cup size 30DD, and recommended sister size 32D.