Estimated size
—
Foot length: —
| System | Size |
|---|
Brand fit notes: Nike runs ½ small. Adidas true to size. Vans true to size (width varies). Converse runs ½ large. New Balance true to size, wide options. Birkenstock comes in EU sizes only — round down for narrow feet.
How the math works
Foot length (cm) → JP exactly. Add ~1.5 cm to length, then 3 × foot-cm − 21 ≈ Mondopoint-ish EU. US men = JP − 18.5. US women = US men + 1.5. UK = US men − 1. CN = (foot length cm × 2) − 10.
Measure standing, end of day, longest toe to heel. Add 5–10 mm of toe room.