US: 12 to Europe Size 104

US: 12: Corresponds to a height baseline of 152 $\text{cm}$ (59.8 $\text{in}$), a chest baseline of 78 $\text{cm}$ (30.7 $\text{in}$), and a sleeve baseline of 59 $\text{cm}$ (23.2 $\text{in}$).

Europe Size 104: Corresponds to a height baseline of 104 $\text{cm}$ (40.9 $\text{in}$), a chest baseline of 59 $\text{cm}$ (23.2 $\text{in}$), and a sleeve baseline of 39 $\text{cm}$ (15.4 $\text{in}$).