Flat Feet in Kids: How the Arch Actually Develops from Birth to Adulthood

If you're a parent, there's a good chance someone, a doctor, a relative, a well-meaning friend, has looked at your toddler's feet and said, "They have flat feet. You should get them insoles."

It comes from a place of genuine concern. And the worry is understandable. Flat feet look like something is missing. The arch isn't there, so surely it needs to be provided, right?

Here's what the research actually shows: every single child is born with flat feet. The arch is not present at birth. It develops gradually over the first decade of life through movement, strength, and use, and the best thing you can do is get out of its way.

This post walks through exactly how the arch develops, what helps it along, what doesn't, and why the standard advice about arch support in children is increasingly being questioned by the research.

 

Every child starts with flat feet, that's completely normal

A newborn's foot has no visible arch at all. The foot is soft, flat, and mostly made of cartilage, not yet bone. This is not a defect. It's exactly how human feet are supposed to start.

A landmark systematic review published in the Journal of Foot and Ankle Research, which analysed 34 studies on paediatric foot development, confirmed that all typically developing children are born with flat feet, gradually developing a medial longitudinal arch during the first decade of their lives. The review goes further, making an important point: a flat foot posture at specific ages is not abnormal. It is typical. Flat equals normal, in the paediatric foot.

Yet despite this, flat feet remain one of the most common reasons parents bring children to medical attention. Parents see a flat foot and assume something is wrong. In the vast majority of cases, nothing is wrong at all, the arch simply hasn't arrived yet.

How the arch develops: a rough timeline

The arch doesn't switch on at a single moment. It emerges gradually, and the timeline varies meaningfully between children. Here's what the research broadly shows:

Birth to age 3: entirely flat, entirely normal

For the first few years of life, the foot is flat by design. The bones are still forming, at six months, the foot is largely cartilage. The last bones begin solidifying around age three. During this phase, the foot's job is not to have an arch; it's to support a child learning to stand and walk. The wide, flat base actually helps with balance during those early unsteady steps.

A fat pad under the foot also makes it look flatter than it is. This is purely structural padding that gradually disappears as the child grows and the foot lengthens.

Ages 3 to 6: the arch begins forming

This is typically when the arch starts to become visible, driven by increasing activity, muscle development, and bone maturation. Research published in ScienceDirect tracking 572 children found a significant shift in arch development around age 7, with the transition from flat to non-flat foot strongly linked to improved one-leg balance, a sign that the foot's muscles and motor control are maturing together.

Not all children develop their arch at the same rate, and that's normal too. Some children show a clear arch by age 4 or 5. Others are still developing at 8 or 9. Both can be perfectly healthy.

Ages 6 to 13: continued development, especially in active kids

The arch continues evolving well into adolescence. A study in Frontiers in Bioengineering found significant increases in arch height between ages 10–13 in girls and 11–13 in boys, meaning foot development is still happening through the early teenage years. Physical activity during this window matters, arch height increased as activity levels increased across both rural and urban children.

By the mid-teens, most children have a stable arch. The NHS notes that most children will have normal arches by age 14, and that children who don't develop a typical arch by this age rarely experience any problems. Flexible flat feet in adults, the most common type, are largely painless and functional.

What actually builds the arch: movement, not support

The arch of the foot is not a bony structure. It's held up by muscles, specifically the intrinsic foot muscles and the tibialis posterior tendon, supported by the plantar fascia ligament. Like any muscle, these grow stronger when they're used, and weaker when they're not.

This is the central insight that changes everything: the arch develops through use, not through being supported externally. A child who moves freely, running on varied surfaces, walking barefoot on grass, climbing, jumping, is giving their foot muscles exactly the workout they need to build a strong arch naturally.

What barefoot time does for developing feet

A major multicenter study published in Scientific Reports compared the foot morphology of 810 children and adolescents who grew up habitually barefoot versus those who wore shoes regularly. The findings were striking: habitual footwear use significantly reduced arch height and hallux angles across all age groups, even when controlling for confounders like ethnicity, BMI, and sex. Children who grew up barefoot had higher arches, wider feet, and fewer toe deformities.

A separate review found that habitually barefoot children had stronger feet during foot strength exercises compared to their shoe-wearing counterparts. Their intrinsic foot muscles, the ones that hold the arch up, were more developed, because they'd been actively used.

Another study specifically on toddlers found that those who habitually wore barefoot shoes from their first steps developed higher plantar arches after just seven months compared to those in conventional shoes. Even very early on, footwear choice shapes the foot.

Varied surfaces matter as much as barefoot time

Walking on flat, uniform surfaces, polished floors, paved footpaths, gives the foot almost nothing to respond to. The muscles activate minimally. Walking on grass, sand, gravel, or uneven ground forces the foot to constantly adapt: the toes grip, the arch engages, the ankle stabilises. It's a full workout that feels like play.

For a child, ten minutes of barefoot play on grass or sand does more for foot development than hours spent in structured shoes on flat floors. This is worth knowing. It's also worth saying: it doesn't have to be complicated. Letting kids take their shoes off in the park is enough.

What doesn't help: the arch support problem

Here's where it gets uncomfortable for the conventional footwear industry.

The standard response to flat feet in children, both from shoe shops and sometimes from medical practitioners, is arch support. Specialised insoles, rigid-soled shoes with built-in arch support, motion-control trainers. The logic seems sensible: the arch isn't there, so prop it up.

But the research doesn't support this approach. The NHS is direct: studies have shown that insoles or arch supports do not help the arches of the foot to develop in childhood. The feet will develop normally without them.

And there's a deeper problem. Arch support takes the load away from the foot muscles, which means those muscles don't need to work. And muscles that don't work don't get stronger. You can end up with a foot that becomes more reliant on support, not less. The arch that was developing naturally gets less stimulus to develop.

A study following toddlers found that arch support footwear did appear to accelerate arch development slightly in the first two years, but critically, arches developed regardless of the footwear worn, suggesting the development was happening anyway. And beyond age three, the arch support provided no additional benefit.

The emerging evidence consistently points in the same direction: for most children, the best thing for arch development is freedom of movement, barefoot time, and shoes that don't restrict the foot's natural function.

What shoes do to a developing foot

Children's shoes, even expensive, well-made ones, typically do several things that aren't ideal for foot development:

•       Narrow the toe box. Most children's shoes taper at the front, squeezing the toes together. The toes are designed to splay out for balance and load distribution. Restricting this from a young age can affect how the forefoot develops and contribute to conditions like bunions later in life.

•       Stiffen the sole. A rigid sole means the foot doesn't have to flex, bend, or respond to the surface below. The muscles that create that flex, and help build the arch, barely activate.

•       Elevate the heel. Even small amounts of heel elevation affect a child's gait and posture, shifting load forward in ways the foot wasn't designed for.

•       Reduce sensory feedback. Bare feet are sensory organs, they send constant information about terrain, pressure, and balance to the brain. Thick-soled shoes muffle this input significantly. Sensory feedback from the foot is important not just for foot development but for motor learning and balance more broadly.

This doesn't mean shoes are harmful, children need protection on rough surfaces and in certain environments. But the less restrictive the shoe, the better for foot development. Light, flexible, wide-toed footwear that allows the foot to move naturally is a very different product from a structured, rigid trainer.

The Indian context: we had it right all along

There's something worth saying here about India specifically.

For most of India's history, children went barefoot or wore minimal chappals. Running on dirt, sand, grass, and uneven ground. Climbing, jumping, playing without thick soles between them and the earth. Foot problems were relatively rare. Arches developed naturally because feet were doing what feet are designed to do.

Research comparing populations in India who never wore structured shoes found exceptionally low rates of foot deformity, broad mobile feet, and strong arches. You can explore that research on our barefoot research page.

Over the past two to three decades, the adoption of Western-style children's footwear, narrow, rigid, heel-elevated, has coincided with a rise in the foot conditions we see in adults: flat feet, plantar fasciitis, bunions, knee pain from altered gait. The connection isn't a coincidence.

The irony is that in trying to give children "better" shoes, more supportive, more structured, more expensive, we may have taken away the very conditions that allow feet to develop well.

Practical things that actually help

If you have a young child and you're thinking about their foot development, here's what the research supports:

•       Let them go barefoot at home as much as possible. Indoor barefoot time is safe, practical, and genuinely valuable. Especially on varied surfaces, carpet, tiles, wooden floors, a mat, every texture activates different parts of the foot.

•       Give them outdoor barefoot time on natural surfaces. Grass in the garden, sand at the beach, soil in the park. These surfaces are the foot's natural training ground. Even short regular sessions make a real difference.

•       Choose shoes that fit like a foot, not like a fashion item. Wide toe box, flexible sole, light construction. Let the toes spread. Check fit regularly, children's feet grow fast and a shoe that fit three months ago may be squeezing the toes now.

•       Encourage active play on uneven ground. Running, climbing, jumping, playing on grass rather than only on flat floors. Physical activity consistently shows up in the research as a predictor of healthy arch development.

•       Don't panic about flat feet before age 6. In the vast majority of cases, what you're looking at is a foot in the process of developing, not a defect. Give it time, give it movement, and don't intervene with arch support unless a specialist has examined the foot and identified a genuine structural issue.

When should you actually see a specialist?

Most flat feet in children need no intervention. But there are signs worth getting checked:

•       The flat foot is rigid, the arch doesn't appear even when the child is on tiptoe or the foot is non-weight-bearing

•       The child complains of foot, ankle, or knee pain regularly

•       There is asymmetry, one foot is significantly flatter than the other

•       The child walks abnormally, turning the feet significantly in or out, walking on the inner edge of the foot

•       Flat feet persist beyond the mid-teens alongside any of the above symptoms

A good paediatric physiotherapist or podiatrist can assess whether what you're seeing is typical developmental variation or something that warrants attention. In most cases, the answer will be: give them more time and more movement.

The bottom line

Your child's flat feet are almost certainly not a problem. They're a starting point. The arch is on its way, built not by insoles or structured shoes, but by the simple, ancient act of a child moving freely on varied ground.

The best investment you can make in your child's foot development doesn't cost anything: barefoot time on grass, unstructured play outdoors, and shoes that fit the natural shape of the foot when protection is needed.

Everything else, the special insoles, the motion control trainers, the orthotics for a seven-year-old with perfectly typical flexible flat feet, is, at best, unnecessary. At worst, it does the work the muscles were supposed to do, and leaves them weaker for it.

Feet are designed to build themselves. They just need the space to do it.

Frequently asked questions

At what age should a child have an arch?

There's no single age. The arch develops gradually throughout the first decade of life. Most research finds significant arch development between ages 3 and 8, with continued development into the early teens. Most children have a stable arch by around age 14. A flat foot before age 6 is almost always completely normal.

Do flat feet affect a child's ability to run and play sports?

In the vast majority of cases, no. Flexible flat feet do not limit sporting ability. Many elite athletes have lower arches. Problems arise when flat feet are rigid, painful, or associated with poor ankle mechanics, not simply because the arch is lower than average.

My child's teacher suggested arch support shoes. What should I do?

This is common, and the advice is well-intentioned. The research, however, doesn't support arch support as a way to develop the arch, the NHS explicitly states this. If you have specific concerns, the right step is a consultation with a paediatric physiotherapist or podiatrist who can assess your child's feet directly. Don't buy expensive insoles based on a visual observation alone.

Are barefoot shoes safe for children?

Flexible, wide-toed, thin-soled shoes designed on barefoot principles are well-supported by research as beneficial for developing feet, provided they offer adequate protection for the environment. For very young children (under 3), actual barefoot time indoors is ideal. When outdoor protection is needed, look for lightweight shoes with a foot-shaped toe box and a sole that bends easily. Both of our adult shoes are built on these principles, and while we don't currently make children's sizes, the principles of what to look for in your child's shoes are the same.

Can adult flat feet be improved?

In many cases, yes, particularly when flat feet in adults are the result of weakened foot muscles rather than structural deformity. Gradual transition to minimal footwear, targeted foot strengthening exercises, and more barefoot time on natural surfaces can all contribute to meaningful improvement.