US: 12-18M to Europe Size 50

US: 12-18M: Corresponds to a height baseline of 80 $\text{cm}$ (31.5 $\text{in}$), a weight baseline of 11 $\text{kg}$ (24.2 $\text{lbs}$), and a chest baseline of 52 $\text{cm}$ (20.5 $\text{in}$).

Europe Size 50: Corresponds to a height baseline of 50 $\text{cm}$ (19.7 $\text{in}$), a weight baseline of 3.4 $\text{kg}$ (7.5 $\text{lbs}$), and a chest baseline of 38 $\text{cm}$ (15 $\text{in}$).