Flat feet show up in lots of kids, fewer teens, and a smaller slice of adults, yet the exact share shifts by age and by how a study defines an “arch.”
Flat feet (also called pes planus) can be a total non-issue, a mild quirk, or a real source of aches. The tricky part is the “percentage” question. Two studies can look at the same town and still report different rates because they measure arches in different ways.
This article gives you usable ranges, explains why the numbers jump around, and helps you figure out where you fit on that spectrum without turning it into a scare story.
Why The Percentage Varies So Much
When people say “flat feet,” they may be talking about a flexible arch that shows up only under body weight, or a rigid arch that stays down all the time. Those are not the same thing, and studies often mix them.
Flat Foot, Flexible Vs. Rigid
Flexible flat foot means the arch looks low when you stand, then it returns when you sit or rise onto your toes. In kids, this pattern is common and often painless. The American Academy of Orthopaedic Surgeons describes flexible flatfoot in children and notes that many kids outgrow it without trouble (AAOS flexible flatfoot in children).
Rigid flat foot means the arch stays low even when you’re off your feet. This is less common and more likely to pair with stiffness or pain.
How Researchers Decide Who Counts
Different methods label “flat” differently. Here are common approaches you’ll see in papers:
- Footprint measures (ink prints, scanners): They estimate arch height by how much of the midfoot contacts the ground.
- Foot posture scoring: A clinician scores features like heel angle and midfoot bulge.
- Arch height measurements: A ruler or device measures the arch at a set point while standing.
- Clinical exam: A clinician checks flexibility, toe-rise response, and alignment.
Because of these differences, a systematic review can only give ranges, not one universal number. A review in the Journal of Foot and Ankle Surgery notes that prevalence estimates vary widely across child and adult studies (Systematic review on pes planus prevalence).
What Percentage Of People Have Flat Feet? By Age And Study Method
If you’re trying to pin down a single percent, the cleanest way is to split the answer by age. Infants and toddlers are often flat-footed because the arch is still forming. MedlinePlus explains that flat feet are common and can be normal in infants and toddlers as tissues tighten with growth (MedlinePlus: Flat feet (pes planus)).
Once kids reach school age, rates drop, but they can still be high if a study uses a footprint cut-off that tags many mild cases as “flat.” By adulthood, flexible flat feet persist in a smaller share, and “acquired” flatfoot from tendon wear adds another slice later in life.
| Group | Typical Ranges Reported | Why The Range Moves |
|---|---|---|
| Infants | High, often the norm | Fat pad and lax tissues hide the arch early on |
| Toddlers (1–3) | Common | Arch is still forming; stance and gait still changing |
| Preschool (3–6) | Meaningful minority | Definitions differ; some studies count mild flexible cases |
| Early school age (6–9) | Lower than preschool | Arch structure matures; measurement cutoffs still vary |
| Late school age (10–12) | Lower again | More stable foot posture; pain-free flexible cases may remain |
| Teens | Smaller share | Many flexible cases resolve; some persist with loose joints |
| Adults | Single digits to low teens in many reports | Study method and population (jobs, activity, body mass) shift results |
| Older adults | Can rise again | Tendon wear and arthritis can lower the arch over time |
Want a concrete data point? One well-cited preschool study in Pediatrics measured 3–6 year olds and reported rates that changed with age and body weight (AAP Pediatrics study on preschool flat foot). That paper is a good reminder: the “kid number” and the “adult number” live in different universes.
Percent Of People With Flat Feet Across Ages
So what should you tell a friend who asks, “How many people have flat feet?” A fair, plain-English answer looks like this:
- In early childhood, low arches are common, often normal, and often flexible.
- Through grade school and the teen years, rates trend downward.
- In adults, many studies land in a lower band, with variation by measurement and by the group being studied.
- Later in life, a new flatfoot pattern can show up when tendons weaken or joints stiffen.
This framing does two things. It respects what research actually shows, and it keeps you from comparing your adult feet to a toddler’s feet and drawing the wrong conclusion.
What Changes The Odds In Real Life
Even within the same age bracket, some patterns show up across studies. None of these are destiny, but they help explain why one family seems full of low arches while another doesn’t.
Body Mass And Load
Heavier body mass can push the arch downward during standing and walking, especially in kids whose feet are still pliable. Some studies find higher flatfoot rates in heavier children, while others find mixed results depending on the test used.
Flexibility And Joint Laxity
Some people are simply more flexible. If your thumbs bend back far or your elbows hyperextend, your feet may also sit flatter under load. In many cases, that’s just your build.
How To Tell If Your Flat Foot Is The Flexible Kind
You don’t need fancy gear to get a clue. These checks won’t replace a clinical exam, but they can steer your next step.
Try The Tiptoe Test
Stand near a wall for balance. Rise onto your toes. If an arch appears and the heel turns inward a bit, that points toward a flexible pattern. If nothing changes and the foot stays stiff, a clinician visit is a better bet.
Do A Simple Wet Footprint
Wet the sole, step on a dark towel or paper, then look at the print. A full midfoot print suggests a lower arch. A narrow band suggests a higher arch. Use this as a rough sketch, not a verdict.
Check Your Shoes
Look at the heel area on a worn pair. If the inner heel is collapsing more than the outer heel, your foot may be rolling inward. Plenty of pain-free people show that pattern. Pain and stiffness are what change the story.
When Flat Feet Stay A Non-Issue
Most flat feet don’t cause problems. Many kids with flexible flat feet run, jump, and play sports with zero fuss. Many adults with low arches lift, hike, and stand all day at work without a second thought.
What tends to matter is not the arch height itself, but the combo of symptoms and function. If you can walk, work, and train without pain, the “percentage” question is mostly trivia.
Signs That Call For A Clinician Visit
If flat feet are new, one-sided, painful, or paired with stiffness, get checked. Adults can develop a fallen arch from tendon strain near the inner ankle, and early care can prevent a spiral of worsening pain.
| What You Notice | What It Can Point To | Next Step |
|---|---|---|
| Pain along the inner ankle | Tendon irritation near the arch | Cut back impact, book an exam |
| One foot flattening fast | Acquired flatfoot pattern | Get assessed soon |
| Stiff foot with little motion | Rigid flatfoot or joint issue | Exam plus imaging if needed |
| Frequent ankle sprains | Instability during gait | Strength work, balance drills, exam if recurring |
| Knee, hip, or back pain that tracks with walking | Chain stress from foot mechanics | Rule out other causes, then address foot setup |
| Kids who avoid running due to pain | Symptomatic flexible flatfoot | Pediatric exam and activity plan |
What Helps When Flat Feet Hurt
Relief usually comes from three buckets: reduce irritation, improve strength and mobility, and change the load your foot sees day to day.
Pick Shoes That Fit Your Needs
A stable heel and a shoe that bends at the toes can cut fatigue on long days. Comfort after a full week matters most.
Use Inserts When Pain Calls For Them
Store-bought inserts often help during a flare. Custom orthotics can help when pain keeps coming back.
Build The Calf And Foot
Tight calves can pull the heel up and push the arch down during walking. A small routine can help:
- Calf stretch: 30–45 seconds, 2–3 rounds per side.
- Heel raises: 2–3 sets of 8–12, slow on the way down.
- Towel scrunches: 2 sets of 30 seconds per foot.
Dial Back Impact During A Flare
If running lights up your inner ankle, swap a few sessions for cycling, swimming, or brisk walking for a couple of weeks. Let the pain settle, then add impact back in small steps.
Parents’ Notes For Kids With Low Arches
Kids’ feet are works in progress. If the child runs and plays without pain, many clinicians just keep an eye on it over time. If pain, frequent tripping, or stiffness shows up, get an exam.
A Simple Checklist To Use Before You Worry
- The arch appears when sitting or on tiptoes.
- Pain is absent during normal walking and play.
- Both feet look similar.
- Shoes wear evenly or only mildly toward the inner heel.
- Stiffness is absent in the midfoot and ankle.
If you tick most of these boxes, your flat feet are likely a normal variant. If pain, stiffness, or sudden change is part of the picture, it’s worth getting evaluated.
References & Sources
- American Academy of Orthopaedic Surgeons (AAOS).“Flexible Flatfoot in Children.”Defines flexible flatfoot and notes that pain-free cases often need no treatment.
- Journal of Foot and Ankle Surgery.“Prevalence and Clinical Factors Associated With Pes Planus Among Children and Adults.”Summarizes how flatfoot prevalence estimates differ across studies and methods.
- MedlinePlus.“Flat feet.”Explains that low arches are common in infants and toddlers and often change with growth.
- American Academy of Pediatrics (Pediatrics).“Prevalence of Flat Foot in Preschool-Aged Children.”Provides prevalence data for ages 3–6 and shows how rates shift with age and cofactors.