Introducing the adidas UltraBoost 21 Crystal White, the ultimate running shoe for athletes. Designed by adidas, this Crystal White shoe offers unparalleled comfort and support. With its sleek design and white color, it’s the perfect choice for any running enthusiast. Push your limits with the adidas UltraBoost 21 Crystal White.
English (United States) English (United States) 
French
German
Dutch
Dutch (Belgium)
Italian
Spanish
English (Canada)
German (Switzerland)
English (UK)
Arabic
English (Australia)
Hungarian
Thai
Portuguese
| U.S. Size | U.K. Size | EU Size | Foot Length (Inches) | Foot Length (cm) |
|---|---|---|---|---|
| 6 | 5.5 | 39 | 9.25 | 23.5 |
| 6.5 | 6 | 39.5 | 9.5 | 24.1 |
| 7 | 6.5 | 40 | 9.625 | 24.4 |
| 7.5 | 7 | 40.5 | 9.75 | 24.8 |
| 8 | 7.5 | 41 | 9.9375 | 25.4 |
| 8.5 | 8 | 42 | 10.125 | 25.7 |
| 9 | 8.5 | 42.5 | 10.25 | 26.0 |
| 9.5 | 9 | 43 | 10.4375 | 26.7 |
| 10 | 9.5 | 44 | 10.5625 | 27.0 |
| 10.5 | 10 | 44.5 | 10.75 | 27.3 |
| 11 | 10.5 | 45 | 10.9375 | 27.9 |
| 11.5 | 11 | 45.5 | 11.125 | 28.3 |
| 12 | 11.5 | 46 | 11.25 | 28.6 |
| 13 | 12.5 | 47 | 11.5625 | 29.4 |
