United Kingdom Size 30D to US: 30A

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

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