Somewhere between 20% and 37% of the population has some degree of flat feet, making it one of the most common foot structures. You can check yourself at home in under a minute with a simple water test, and a few other signs from your shoes and your body can confirm what you find.
The Wet Foot Test
This is the quickest way to assess your arch at home. You need a flat, smooth surface where a wet footprint will show up clearly: a concrete sidewalk, a piece of colored paper, or cardboard all work well.
Wet the entire bottom of your foot, then step down with your full weight on the surface. Step off and look at the shape you left behind. A normal arch leaves a print with a clear inward curve along the middle of the foot, where the arch lifts away from the ground. If your footprint looks like a solid oval with toes on top, and there’s little or no curve missing from the inside edge, you have flat feet. The more filled-in that middle section is, the lower your arch sits.
The Tiptoe Test
Stand barefoot on a hard floor and rise up onto your tiptoes. Have someone watch the inside of your foot, or do this in front of a mirror. If an arch appears along the inside of your foot when you’re on tiptoe, you have what’s called a flexible flat foot. The bones and joints are capable of forming an arch; they just don’t maintain it under your full body weight. This is the most common type and often causes no problems at all.
If no arch forms when you rise onto your toes, or if the movement feels stiff and limited, that points to a rigid flat foot. Rigid flat feet involve structural changes in the bones or joints and are more likely to cause pain or need treatment.
Check Your Shoes
Your worn-out shoes tell a story about how your feet hit the ground. Flip over a pair you’ve worn regularly for a few months and look at the outsole. Flat feet cause overpronation, meaning your foot rolls inward too far with each step. This shows up as excessive wear along the inner (medial) edge of the sole, especially near the ball of the foot. If the inner side of your shoe is noticeably more worn down than the outer side, that’s a strong signal your arches are collapsing inward during walking or running.
You can also look at your shoes from behind while they sit on a flat surface. If they lean inward, that tilt reflects the same inward roll.
The “Too Many Toes” Sign
This one requires a friend or a mirror behind you. Stand naturally with your feet pointing forward and have someone look at your feet from directly behind. Normally, only the pinky toe and maybe the fourth toe peek out to the side. If more than two toes are visible flaring out on the outer edge of your foot, it means your foot has shifted into an outward-pointing alignment that commonly accompanies flat feet. Doctors call this the “too many toes” sign, and it’s one of the first things they check during a foot exam.
Symptoms That Point to Flat Feet
Many people with flat feet never experience pain, especially if they’ve had low arches their whole life. But when flat feet do cause trouble, the pain tends to follow a pattern that starts in the feet and works its way up.
The earliest discomfort usually shows up as soreness along the inner ankle or the arch itself, particularly after walking or standing for long stretches. Shin splints are also common because your lower leg muscles work harder to compensate for the lack of arch support. Over time, the misalignment can travel upward, contributing to pain in your knees, hips, and lower back. If you’ve been dealing with pain in any of these areas without an obvious cause, your foot structure is worth investigating.
Flat Feet That Develop Later in Life
Not everyone with flat feet was born that way. Adults can develop flat feet gradually, most often because the tendon running along the inner ankle (the one responsible for holding up your arch) weakens or tears over time. This is the single most common cause of flat feet appearing in adulthood.
The early warning sign is pain and swelling along the inner side of the ankle. As the condition progresses, the arch visibly drops, the foot starts pointing outward, and activities like walking uphill or climbing stairs become painful. A useful self-check is the single-leg heel raise: stand on one foot and try to rise onto your toes. If you can do it but it hurts, or if you can’t complete the movement at all, the tendon supporting your arch may be damaged.
This type of flat foot tends to get worse without intervention, so noticing the change early matters. If your arch was always normal and has recently started to flatten, or if one foot looks noticeably flatter than the other, that’s different from lifelong flat feet and worth getting evaluated.
Flexible vs. Rigid: Why It Matters
The distinction between flexible and rigid flat feet shapes what, if anything, needs to happen next. Flexible flat feet are extremely common, especially in children, and most people with them live without symptoms their entire lives. The arch is structurally present but doesn’t hold up under weight. Supportive shoes or over-the-counter insoles are usually enough if discomfort does appear.
Rigid flat feet are less common and more likely to cause persistent pain or limit mobility. Because the foot can’t form an arch in any position, it doesn’t absorb shock as effectively, and pressure gets distributed unevenly. This type typically requires professional assessment and may need custom orthotics or, in some cases, further treatment. The tiptoe test described above is the simplest way to tell which type you’re dealing with.