United Kingdom Size 18G Standard Stud to US: 12mm Classic Huggie

United Kingdom Size 18G Standard Stud: Features a post thickness of 1 $\text{mm}$ (0.0394 $\text{in}$), hoop inner diameter of 0 $\text{mm}$, drop length of 6.5 $\text{mm}$, gemstone carat equivalence of 0.50 ct - 1.00 ct, and earring style Stud / Solitaire.

US: 12mm Classic Huggie: Features a post thickness of 1 $\text{mm}$ (0.0394 $\text{in}$), hoop inner diameter of 12 $\text{mm}$, drop length of 12 $\text{mm}$, gemstone carat equivalence of Pave Accent, and earring style Huggie / Medium Lobe.