What Is Stack Height? The Often-Overlooked Factor When Choosing Running Shoes
When you buy new running shoes, what catches your attention first? The brand? The model? The colour? Or just the price tag? Plenty of runners choose their shoes without ever hearing the term stack height. Put simply, it means the height of the sole. If it has never been on your radar, here is the catch: this measurement can make a substantial difference to your performance, injury risk and how running feels. In this guide, I will walk you through stack height from the beginning. Let’s see what those millimetres are all about.
What Is Stack Height?
Stack height is the total thickness, measured in millimetres, of the materials between the bottom of the shoe and the ground. This includes foam, the midsole, the outsole and any carbon-fibre plates. Carbon-fibre plates are usually found in more expensive performance and racing shoes. The shoe’s inner lining and insole are not included in this measurement.
Shoes have separate stack height measurements at the heel and forefoot. The difference between the two is called the heel-to-toe drop, usually shortened to “drop”. For example, a shoe with 36 mm at the heel and 28 mm at the forefoot has an 8 mm drop.
Put simply: stack height is the buffer between your foot and the ground. The higher the number, the more material there is underneath you.
Why Does Stack Height Matter So Much?
When most of us start running, we buy a pair of shoes and head out. That is perfectly normal. We are not all professional athletes, after all. Some of us run to get fitter; others run to clear our heads. Still, stack height matters more than we might think.
1. Ground Feel: How Much Difference Does Stack Height Make?
A low-stack running shoe gives you a more direct sense of contact with the ground. Some minimalist runners prefer that feeling. A higher sole reduces it, so you feel less of the surface beneath you.
2. Cushioning and Protection
Over longer distances, a high-stack shoe does a better job of absorbing the cumulative load on muscles and joints. Shoes designed for marathons or ultra-trail running often have stack heights of 35–40 mm or more.
3. The Biomechanical Effect
Together with drop—the height difference between the heel and forefoot—stack height influences how your body first meets the ground. A combination of high stack and high drop increases the tendency to land on your heel. Lower stack heights, by contrast, encourage more forefoot and midfoot contact.
4. Stability
The thicker the sole, the higher your centre of gravity. In theory, that increases the risk of losing your balance. On uneven trails, this becomes even more relevant.
Stack Height Ranges and What They Mean
| Category | Forefoot Stack Height | Typical Use |
|---|---|---|
| Minimalist / barefoot | 0–10 mm | Natural running, strength training |
| Low stack | 10–20 mm | Speed sessions, trail running |
| Medium stack | 20–30 mm | Versatile use, everyday running |
| High stack | 30–40 mm | Marathons, long-distance running |
| Maximalist | 40 mm+ | Ultramarathons, very high cushioning needs |
The “More Cushioning = Fewer Injuries” Myth
If you have never looked into the subject, it is easy to assume that more cushioning means fewer injuries. You certainly would not be the first person to think so. High stack heights are often assumed to prevent injury. However, research such as a 2018 study published in Scientific Reports has suggested that highly cushioned shoes can increase leg stiffness and impact loading without runners realising it. In other words, we may land harder because we feel protected. Researchers have called this the shoe cushioning paradox.
Researchers also stress the need for care when switching to minimalist shoes, as an abrupt transition can lead to stress fractures. If you have spent years running in heavily cushioned shoes, your body gets used to them. Move to a lower stack height and your muscles and tendons face loads they are not accustomed to.
The takeaway: the right stack height is neither the highest nor the lowest. It is the one that suits your biomechanics, training volume and running history.
Which Stack Height Suits Which Runner?
Stack Height for Beginners
A medium stack height of 20–30 mm and a moderate drop of 6–10 mm offer an ideal balance to start with. Your body needs time to get used to running. During that process, moderate stack and drop values provide support without going to extremes.
Runners Focused on Speed
If you focus on half marathons or shorter races, you might choose a low-to-medium stack height of 15–25 mm. Models in this range reduce energy losses during transfer and allow a quicker response from the ground. If you have researched running shoes or spent any time watching running content, you have probably come across carbon-plated shoes. Although these shoes often have stack heights of 35–40 mm, the carbon plate inside changes the energy equation entirely.
Stack Height for Marathon and Ultra Runners
Beyond 40 km, fatigue can cause your form to deteriorate and impact loads to increase. For these distances, shoes with stack heights of 30–40 mm or more are therefore the recommended choice.
Stack Height for Trail Runners
On trails, a high stack height can compromise stability. Lower stack heights give you more ground feel, helping you adapt to rocky surfaces. A range of 20–28 mm offers a balanced option for trail running.
Runners with a History of Injury
Injuries are part of sport. Whether you have just started running or have been doing it for years, the possibility is always there. If you have had a serious injury or a chronic knee problem, I recommend seeing a physiotherapist or sports physician before choosing your drop and stack height. If your joints need a break from impact for a while, you could also consider lower-impact alternatives such as rowing.
What to Keep in Mind When Changing Stack Height
There is no rule saying your stack height has to stay the same forever. You can change it over time. The key is not to rush. Say you currently run in a shoe with a 30 mm stack height and want to move towards something more minimalist. Following a transition plan will help.
- Do not reduce stack height by more than 10 mm in one go. Give your body time to adjust.
- Start by using your new shoes for just 1–2 training sessions per week.
- Make more room for exercises that strengthen your feet and legs during the transition. This is an important step many of us skip.
- Do not be afraid to take your time. An adaptation period of 6–8 weeks might sound long at first, but it helps you get through the transition safely.
The reverse move—from a lower stack to a higher one—is generally easier to tolerate.
A Practical Shopping Guide: How to Read Stack Height Specs
When we first start running, many of us buy shoes because we like how they look. From now on, though, look for these details on the box or product page:
- “Stack height: 36 mm / 28 mm” → 36 mm at the heel, 28 mm at the forefoot.
- “Drop: 8 mm” → The difference between the two. In this case, 36 − 28 = 8.
- Some brands list only the drop, without specifying stack height. If that happens, check the brand’s technical information page.
A YouTube channel I watched recently mentioned that most runners preferred local shops. The reason was the extra technical advice available there. Türkiye also has a small number of shops dedicated to running. This is not a criticism of the brand—it is simply the first example that comes to mind—but if you walk into Boyner, a Turkish department store chain, and ask about heel-to-toe drop, the sales assistant may not be able to help much.
Here are the stack heights associated with some popular shoe ranges:
| Technology / Model Range | Typical Stack Height |
|---|---|
| Nike ZoomX Vaporfly series | ~36–40 mm |
| Hoka Clifton series | ~29–33 mm |
| Saucony Kinvara series | ~24–26 mm |
| Vibram FiveFingers | 3–6 mm |
| New Balance Fresh Foam series | ~28–34 mm |
Instead of searching each brand’s website separately, you can use our running shoe selector. It lists stack height, drop and weight for models sold in Türkiye, along with the source and the date the information was checked.
Conclusion: One Stack Height Does Not Fit Everyone
Stack height is a running shoe specification many of us overlook. Some runners may never even have heard of it. It is a slightly technical subject that takes a little research, which helps explain why. Yet this measurement plays a fundamental role in how your shoes work with your body.
To choose a suitable stack height, ask yourself:
- How many kilometres do I run each week, and on which surfaces? The ground you run on makes a real difference.
- Have I considered my injury history? Have I been injured before, and if so, what kind of injury was it?
- What is the stack height of my current shoes, and how does it feel? Is anything uncomfortable?
- Is my priority speed, distance or everyday comfort?
Your answers will help point you towards a suitable stack height range. You can read reviews that examine the technical details of a model you like. If there is a specialist running shop near you, getting technical advice there can also be a sensible move.
For more guides on running shoes, training and choosing equipment, take a look at our Running category.
This article provides general information about running biomechanics and shoe technology. If you have an injury or chronic pain, consult a sports physician or physiotherapist.