Running shoe fit is where most injury-adjacent problems start, and the industry has spent a decade walking back the advice it gave in the previous one. The pronation-control model that once drove every fitting has largely given way to a simpler principle: comfort predicts outcomes better than any gait category.
Size up, and measure late
Running shoes should be roughly half to a full size larger than your dress shoes. Feet swell during a run — meaningfully — and a shoe that fits perfectly in a shop at 10am will bruise your toenails at mile eight. Shop in the evening, wear your running socks, and leave a thumb’s width between your longest toe and the front of the shoe.
Width matters as much as length. If the upper bulges over the midsole edge when you stand, you need a wide fitting, not a longer shoe. Going up a size to gain width is the most common fitting mistake.
Match the shoe to your foot shape
| Foot characteristic | What to look for |
|---|---|
| High arch | More cushioning and a flexible midsole; high arches absorb shock poorly on their own. |
| Flat or low arch | A firmer, more structured midsole. Try both neutral and stability and pick on comfort. |
| Wide forefoot | Wide fittings or brands cut on a naturally roomy last; check the toe box, not the size. |
| Narrow heel | A well-shaped heel counter and runner’s-loop lacing to stop slipping. |
| Bunions | Soft, seamless knit uppers with minimal overlays across the forefoot. |
Drop, stack and what they change
Heel-to-toe drop is the height difference between heel and forefoot. Higher drops (8–12mm) shift load toward the knee; lower drops (0–6mm) shift it toward the calf and Achilles. Neither is inherently better, but changing drop abruptly is a reliable way to injure yourself. If you switch, do it gradually over several weeks.
Stack height — total foam under the foot — has climbed steeply across the market. More foam means more cushioning and usually more weight, with some loss of ground feel and stability on uneven surfaces.
Rotate if you can
Two pairs alternated will outlast two pairs worn sequentially, because midsole foam needs time to decompress between runs. Rotation also varies the load on your tissues slightly, which is generally protective. A daily trainer plus one lighter, faster shoe covers most people’s needs.
When to replace them
The often-quoted 500–800km range is a starting point, not a rule — body weight, surface and gait all move it. The better signals are physical: midsole creasing that does not spring back, visible wear through to the outsole, and new aches in the knees or shins that appear without a change in training. Track mileage per pair if you rotate, or your replacement point will always be a guess.
