Running Shoe Sizing Guide
Running shoes are sized for the foot under load, not at rest. This guide covers the fit rules that matter and the ones that do not.
The half-size rule
Go half a size up from your measured length for road running, and a full size up for anything over 20 km. Your foot swells and lengthens as you run; a shoe that fits in the shop will not fit at hour two.
Width matters more than length
| Fitting | Code | Suits |
|---|---|---|
| Narrow | B / 2A | Low-volume feet, often with a high arch |
| Standard | D | Most runners |
| Wide | 2E | Broad forefoot, bunions |
| Extra wide | 4E | Significant forefoot spread |
Checking the fit
- Thumb-width between your longest toe and the end of the shoe.
- No pressure across the widest part of the foot when standing.
- Heel locked in — lift onto your toes; the heel should not slip.
Try shoes on with the socks you actually run in. A technical sock and a cotton sock are close to half a size apart.