Europe Size 21.5 to US: 4

Cross-market children’s footwear conversion mapping 21.5 specifications into 4 for sneakers, boots, sandals, dress shoes, slippers, and dance shoes.

From Standard & Size

Converted Equivalent

Based on row equivalence: US 5 | EU 21.5 | Foot Length 13.0 cm

Standard cross-walk matching active anthropometric row parameters.

Analyzing Footwear Size Equivalence Across Markets

Europe Size 21.5: Corresponds to a foot length of13.0 $\text{cm}$ (5.1 $\text{in}$ ), estimated age 2y, and Mondopoint 130 $\text{mm}$ .

US: 4: Corresponds to a foot length of 12.0 $\text{cm}$ (4.7 $\text{in}$ ), estimated age 18-24m, and Mondopoint 120 $\text{mm}$ .