How to Tell If You Have Flat Feet: 3 Simple Tests for Runners

To tell if you have flat feet, perform the "wet test" to see your footprint shape, observe if your ankles roll inward excessively when you run, and check for a significant collapse of your arch when standing. These three simple assessments help runners understand their foot type and choose appropriate running shoes for support and injury prevention. Understanding your own biomechanics is the single most important step in buying the right gear.

As a running coach, I've seen countless runners come into our shop convinced they have a certain foot type, only to discover something completely different once we put them on the treadmill. Let's walk through the exact same tests we use in our professional fittings so you can get a clear picture of your feet.

What is the Easiest At-Home Test for Flat Feet?

The easiest initial check is the "wet test." It's simple, fast, and gives you a great visual of your foot's static structure. It won't tell you what your foot does when it's in motion—a crucial distinction—but it's the perfect starting point.

How to do the wet test:

1. Pour a thin layer of water into a shallow pan or baking sheet.
2. Place a piece of heavy paper, a flattened paper bag, or a piece of cardboard next to the pan.
3. Step into the water with one foot, making sure the entire sole is wet.
4. Carefully step onto the paper, putting your normal standing weight on that foot for a second or two.
5. Step off and examine the footprint you've left behind.

Now, compare your print to the descriptions in this table.

Footprint Analysis for Runners

Footprint Shape	Arch Type	What It Means for Runners
A full, solid shape with almost no curve on the inside.	Flat Arch (Pes Planus)	This indicates your arch makes full or near-full contact with the ground when you stand. You are more likely to overpronate, where the arch collapses inward under the load of running. This can lead to stress on the ankles, shins, and knees. You will likely benefit from shoes with stability features.
A distinct curve on the inside, with about half the arch visible.	Normal Arch	Your foot structure is designed to absorb shock effectively. You will likely do well in neutral running shoes, but you should still check for overpronation. About 50% of runners with "normal" arches still overpronate to some degree.
A very thin line connecting the heel and the ball of the foot.	High Arch (Pes Cavus)	Your arch is high and rigid, making it a poor shock absorber. The pressure is concentrated on your heel and the ball of your foot. You should look for highly cushioned, flexible neutral shoes. Avoid stability shoes, as they can make your rigid foot even more so and shift stress to your knees.

A word of caution: The wet test only shows your foot's shape while standing still. I recently worked with a runner whose wet test showed a perfectly normal arch. However, his chief complaint was shin splints. When we put him on the gait cam, we saw his arch completely collapse with every step. The wet test lied; the motion told the truth. That's why the next test is critical.

How Can a Video Tell Me if I Have Flat Feet?

A video of you running is the gold standard for at-home gait analysis. It shows what your foot and ankle do dynamically, under load, which is what actually matters for injury risk and shoe choice. This is the test that separates anatomical flat feet from functional overpronation.

How to film your running gait:

1. Set up your phone on the floor behind a treadmill. If you don't have a treadmill, have a friend film you running away from them in a straight line on a flat, even surface.
2. The camera should be level with your ankles.
3. Record in slow-motion if your phone has the feature.
4. Run for 30-60 seconds at your normal, easy pace. It's best to do this barefoot or in thin socks to see the foot's natural motion.

What to look for: Watch the playback, focusing on the moment your foot lands and rolls through your stride. Look at your Achilles tendon and heel bone (the calcaneus). Do they stay relatively vertical, or do they angle inward? An excessive inward roll of the ankle and collapse of the arch is overpronation. This motion forces your lower leg to rotate internally, which can be a source of shin, knee, and even hip pain.

In our fit sessions, we look for the degree of this inward roll at the subtalar joint (the joint below the ankle). A small amount is natural and healthy. An excessive amount, especially if it's uncontrolled and rapid, is what we aim to support with stability shoes.

What is the Navicular Drop Test and Do I Need It?

For those who want to get more technical, the navicular drop test quantifies how much your arch actually collapses under your body weight. The navicular is a bone at the top of your arch on the inside of your foot.

1. Sit in a chair with your feet flat on the floor.
2. Find your navicular bone. It's the prominent bump on the inside of your midfoot, just below and in front of your ankle bone.
3. Mark its height. Use a small ruler or index card to measure its height from the floor and mark it.
4. Stand up, with your feet in the same position and your weight distributed evenly.
5. Re-measure the height. Without moving your foot, measure the height of the navicular bone again.

The difference between the seated and standing height is your navicular drop. A drop of more than 10 millimeters (about 0.4 inches) is generally considered excessive and is a strong indicator of a flexible, collapsing arch that could benefit from support.

The Tradeoff: This test is more precise but can be tricky to perform accurately on your own. We typically use it in the shop to confirm what we see on the gait camera, especially for runners with a history of arch-related injuries like Plantar Fasciitis or PTTD. For most runners, the wet test plus a gait video is more than enough information.

What Should I Do If These Tests Show I Have Flat Feet?

First, don't panic. Many elite athletes run on flat feet. The goal isn't to "correct" your foot, but to support it appropriately so it can handle the repetitive stress of running.

• If you have a flat footprint AND see significant inward ankle roll (overpronation): You are a prime candidate for a stability running shoe. These shoes use features like a firmer medial post (a wedge of dense foam under the arch) or holistic GuideRails (as seen in Brooks shoes) to slow the rate of pronation. Start by looking at our guide to the best running-shoes for flat feet.
• If your footprint is normal or high-arched BUT you still see inward ankle roll: You have what's called flexible pronation. You might benefit from a mild stability shoe or even a stable neutral shoe. Over-correcting with a heavy-duty stability shoe could cause problems. Trying an over-the-counter insole in a neutral shoe is also a great option. See our list of the best insoles for flat feet runners.
• If you have a flat footprint BUT your ankle stays upright: Your body has likely adapted to control the motion. You may not need a stability shoe at all and could find them overly rigid. A stable neutral shoe would be a better starting point.

What I do not recommend: Do not immediately buy the most rigid motion-control shoe you can find just because a wet test showed a flat foot. We see this all the time, and it often leads to other issues. A runner came to us with knee pain after self-prescribing a motion-control shoe. His arch was flat, but his gait was perfectly neutral. The shoe was forcing his foot to supinate (roll outward), creating a new, worse problem.

Remember, the goal is to guide the foot, not block it. And if you have sharp, persistent, or debilitating pain, your first stop should be a podiatrist or physical therapist. They can provide a clinical diagnosis and rule out more serious issues. This guide is for educational and shoe-fitting purposes.

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