Running shoes: what drop and stack actually change
Two numbers on a running shoe tell you more than the colourway: the stack height and the drop. Both are stated by the maker, both are easy to compare, and both change how the shoe feels in a way the marketing copy does not describe.
Drop is the slope under your foot
Heel-to-toe drop is the difference in height between the heel and the forefoot. A higher drop tilts you forward and puts more of the landing on the heel; a lower drop is flatter and loads the calf and Achilles more. Neither is better. What matters is change: moving from a high-drop shoe to a low-drop one in a single step is how runners pick up calf and tendon complaints.
Stack is how much is between you and the ground
Stack height is the total thickness of the sole. High stacks are softer and more protective over long distances and less stable on uneven ground; low stacks give more feel and less cushioning. Again, the sensible comparison is to the shoe you run in now.
Fit is a width, not just a length
Makers that publish widths are giving you a real choice. Running shoes run narrow more often than wide, and a shoe that is the right length but the wrong width is returned far more often than one that is simply the wrong size. Check whether the listing states a width option before you order.
What to check before you buy
- Drop and stack of the shoe you run in today — then compare, and change gradually.
- Whether a width is stated, and which.
- The surface: road, trail and track outsoles are different products.
- Return terms, because fit is the one thing no listing can settle for you.
Some links on ShopCursor are affiliate links. See the affiliate disclosure. Commission never changes which products we pick or the order they appear in.