What Is Stack Height and Why Does It Matter?
Stack height refers to the amount of material between your foot and the ground. In simple terms, it’s how tall a shoe is. While that might sound like a minor detail, it has a big impact on how a shoe feels and performs.
Stack height refers to the total amount of material between your foot and the ground — in plain terms, how tall a shoe is from the ground up. It's measured in millimeters at both the heel and the forefoot, and while it might sound like a minor technical detail, stack height has a significant impact on how a shoe feels, performs, and what it's best suited for in your training.
How Stack Height Is Measured
Stack height is measured at two points: the heel and the forefoot. When you see a shoe listed as "40mm heel / 32mm forefoot," that means there's 40mm of material under your heel and 32mm under the ball of your foot. The difference between those two numbers is your heel drop — in this case, 8mm.
Running Warehouse and most major retailers now list both heel and forefoot stack heights on every shoe page, making it easy to compare before you buy.
Stack Height Categories
- Minimal (under 18mm forefoot): Thin midsoles for a grounded, natural feel. Track spikes, minimalist shoes, and some racing flats.
- Low (19–23mm forefoot): Light cushioning with a connected feel. Performance trainers and some trail shoes.
- Medium (24–28mm forefoot): Versatile middle ground. Works well across all paces and distances.
- High (29–34mm forefoot): Thick, protective cushioning. Daily trainers and long-run shoes.
- Maximal (35mm+ forefoot): Maximum cushioning. Recovery and long-distance comfort shoes.
The Case for High Stack Shoes
Higher stack shoes absorb more impact energy before it reaches your joints, which makes them genuinely valuable for long runs, recovery days, and high-mileage training weeks. This is one reason marathon shoes have trended heavily toward max-stack designs in recent years — more foam under your feet means less fatigue accumulation over 26.2 miles.
The ASICS Gel Nimbus 28, HOKA Bondi 9, and New Balance 1080 v15 are examples of high-stack daily trainers built for comfort, protection, and long-distance durability. These are shoes designed to make easy miles feel effortless and protect your legs across big training weeks.
The tradeoff is stability. A taller shoe creates a higher center of gravity, which can feel less secure on sharp turns, uneven terrain, or very fast efforts. Most high-stack daily trainers compensate with wider bases and rocker geometry to maintain smooth transitions.
The Case for Moderate Stack Shoes
Moderate stack shoes offer a compelling middle ground — enough cushioning for comfort on longer efforts, but a lower profile that feels more connected, responsive, and stable at faster paces. The HOKA Mach 7, Saucony Ride 19, and Nike Pegasus 42 sit in this range and are among the most versatile shoes in any category. They handle easy runs, tempo workouts, and long runs with equal competence.
Lower stack also improves ground feel — your ability to sense the surface beneath you. Many runners find this improves proprioception and confidence, especially during faster efforts or on technical surfaces. This is why many speed-focused shoes maintain a relatively modest stack even when loaded with advanced foams.
It's Not Just About How Much Foam — It's How the Foam Behaves
A high stack of soft PEBA foam feels completely different from a high stack of traditional EVA — even if the measurements are identical. Next-generation supercritical foams like ZoomX, PWRRUN PB, and Infinion are lighter, bouncier, and more energy-returning than EVA, which is why modern max-stack super shoes can feel faster than lower-stack traditional trainers despite having significantly more foam underfoot.
The Nike Vaporfly 4 is a perfect example — its 39.5mm heel stack would classify it as maximal, yet it's among the fastest racing shoes available because of the ZoomX foam and carbon plate combination. Stack height sets the parameters, but foam compound and plate geometry determine performance within those parameters.
Matching Stack Height to Your Training
Run Type | Recommended Stack |
|---|---|
Easy / recovery runs | High or maximal |
Long runs | High or maximal |
Tempo / threshold runs | Low to moderate |
Speed workouts / track | Low to moderate |
Race day | Varies by foam — see super shoes |
Want to compare stack heights across different shoes? Use our comparison tool to filter by heel stack, forefoot stack, and cushion level to find the right fit for every run in your training week.
