Europe Size 21 to US: 9-XW

Cross-market children’s footwear width fitting conversion mapping 21 specifications into 9-XW for Brannock infant/child grades, M/W/XW sizing indexes, and ball width dimensions.

From Standard & Size

Converted Equivalent

5-N

Based on row equivalence: US 5-N | EU 21 | Foot Length 12.5 cm

Standard cross-walk matching active anthropometric row parameters.

Europe Size 21 to US: 9-XW Width Conversion

Analyzing Shoe Width and Fitting Equivalence Across Markets

Europe Size 21: Corresponds to a foot length of 12.5 $\text{cm}$ (4.9 $\text{in}$ ), ball width of 5.3 $\text{cm}$ (2.1 $\text{in}$ ), grade Narrow (B), growth margin 0.8 $\text{cm}$ , estimated age 18-24m, Mondopoint 125 $\text{mm}$ , and fit type Toddler Narrow (US 5 / Width B).

US: 9-XW: Corresponds to a foot length of 15.5 $\text{cm}$ (6.1 $\text{in}$ ), ball width of 7.1 $\text{cm}$ (2.8 $\text{in}$ ), grade Extra-Wide (4E), growth margin 0.9 $\text{cm}$ , estimated age 4-5y, Mondopoint 155 $\text{mm}$ , and fit type Toddler Extra-Wide (US 9 / Width 4E).