Key takeaways
- Stack height is the thickness of material between your foot and the ground (in mm).
- It's usually given at the heel and forefoot; it indicates cushioning and ground clearance.
- High stack = maximal cushioning and protection, but less ground feel and stability.
- Low stack = more ground feel and stability, but less cushioning.
From the 'stack' of material under the foot.
What stack height is
Stack height is the thickness of material (midsole, outsole, insole) between the bottom of your foot and the ground in a shoe, usually measured in millimeters at the heel and forefoot. It tells you how much cushioning is underfoot and how far off the ground you’re standing.
How it affects feel and performance
- High stack — maximal cushioning and protection (soft landings, comfort on long distances, rock protection on trails), but less ground feel and a higher, sometimes less stable platform.
- Low stack — more ground feel, stability, and agility, but less cushioning.
Neither is universally better — it’s a trade-off based on distance, terrain, and preference.
For a rocky 100-miler, a runner picks a high-stack shoe to protect their feet over hours of pounding — accepting less ground feel — while for short, technical races they prefer a lower-stack shoe that lets them feel the trail and react nimbly.
Stack height vs drop
They’re related but distinct: stack height is the total material under the foot (given for heel and forefoot), while heel-to-toe drop is the difference between heel and forefoot stack. A shoe can have a high stack with a low drop, or any combination (including zero-drop). Both numbers together define the geometry, alongside features like a rock plate and the toe box.
The bottom line
Stack height is the thickness of material between your foot and the ground (in mm, at heel and forefoot) — how much cushioning is underfoot. High stack means plush protection but less ground feel and stability; low stack means a connected, stable, agile feel but less cushion. It's a personal trade-off based on distance, terrain, and style, and works together with heel-to-toe drop to define a shoe's geometry.
Frequently asked questions
What is stack height in running shoes?
Stack height is the total thickness of shoe material — midsole, outsole, and any insole — between the bottom of your foot and the ground, usually measured in millimeters. It's typically reported at both the heel and the forefoot. In simple terms, it tells you how much cushioning is underfoot and how far off the ground you're standing.
How does stack height affect how a shoe feels and performs?
Higher stack height means more cushioning and protection from the ground (softer landings, more comfort on hard surfaces and long distances, protection from rocks on trails), but typically less 'ground feel' and a higher, sometimes less stable platform. Lower stack height means you feel the ground more (better proprioception and a more connected, stable, agile feel) but with less cushioning. Neither is universally better — it's a trade-off based on preference, distance, terrain, and running style.
How does stack height relate to heel-to-toe drop?
They're related but distinct. Stack height is the total amount of material under the foot (and is given separately for heel and forefoot). Heel-to-toe drop is the difference between the heel stack and the forefoot stack — how much higher the heel sits than the toes. So a shoe can have a high stack height with a low drop (lots of cushion, but level heel-to-toe) or various combinations. Both numbers together describe the shoe's geometry and feel.
Sources
- Running shoe design — American Council on Exercise
- Footwear & biomechanics — American Academy of Podiatric Sports Medicine