To measure a baby’s foot, place it flat on a piece of paper, trace the outline with a pencil, then use a ruler to measure from the heel to the longest toe. The whole process takes about two minutes and gives you a reliable length to match against shoe size charts. Getting it right matters more than you might think, because babies’ feet are mostly soft cartilage, and poorly fitting shoes can actually shape how those bones develop.
What You Need
A blank sheet of paper, a pencil, a ruler, and a flat surface like a hardwood floor or table. That’s it. Avoid measuring on carpet, which can shift under the paper and throw off your tracing.
Step-by-Step Tracing Method
Place the paper on your flat surface. Press your baby’s foot gently onto the paper so it lies flat, with toes uncurled and spread naturally. If your baby is old enough to stand, have them put their weight on the foot, since a weight-bearing foot spreads wider and longer than one dangling in the air. For younger babies who aren’t standing yet, gently press the sole down to mimic that spread.
Hold the pencil upright (perpendicular to the paper) and trace closely around the foot. Keeping the pencil vertical prevents you from angling inward or outward, which would shrink or inflate the outline. Once you have the tracing, use your ruler to measure the distance from the very back of the heel to the tip of the longest toe. Write down the number in both inches and centimeters if you can, since shoe brands use different units.
Repeat with the other foot. Slight size differences between left and right are completely normal. Always use the longer measurement when choosing a shoe size.
Measuring Width
Length alone doesn’t tell the full story. To check width, measure across the widest part of the tracing, typically the ball of the foot just below the toes. Compare that number to width charts to determine whether your baby needs a medium, wide, or extra-wide shoe. For reference, a size 3 infant shoe in medium width is about 2⅛ inches across, while a wide is 2⁷⁄₁₆ inches and extra wide is 2⅝ inches. By size 5, those numbers climb to roughly 2¼, 2⅝, and 2¹³⁄₁₆ inches.
If your baby’s foot looks noticeably chubby on top (high volume over the instep), standard shoes may feel tight even when the length and width are correct. In that case, look for brands that offer wide or adjustable-closure styles rather than simply sizing up, which leaves too much length.
Converting Length to Shoe Size
Once you have a length in centimeters, you can match it to standard sizing across US, UK, and EU systems. Here are the most common infant sizes:
- 10.1 cm (about 4 inches): US 3 / UK 2 / EU 18
- 11.7 cm (about 4.6 inches): US 5 / UK 4 / EU 20
- 13.4 cm (about 5.3 inches): US 7 / UK 6 / EU 23
- 15.1 cm (about 5.9 inches): US 9 / UK 8 / EU 25
- 16.8 cm (about 6.6 inches): US 11 / UK 10 / EU 28
These are foot lengths, not shoe lengths. The shoe itself will be slightly longer to allow growing room, which brings us to fit.
How Much Room to Leave
The American Academy of Pediatrics recommends about a finger’s width, roughly half an inch, between the tip of the big toe and the front of the shoe’s insole. This gives toes space to wiggle and accommodates the rapid growth that happens in the first few years. Less than that and you risk compressing the toes. More than that and the shoe can slip, causing blisters from friction.
When to Measure (Time of Day Matters)
Feet swell throughout the day, and baby feet are no exception. Avoid measuring first thing in the morning when feet are at their smallest. Instead, measure in the afternoon or evening after your baby has been active for a few hours. This gives you a tracing that reflects the foot at its largest, so the shoes you buy won’t feel tight by the end of the day.
How Often to Remeasure
Baby feet grow fast, and the pace changes with age. A study tracking children from ages one to five found a clear pattern: babies under 15 months outgrow a half-size in less than two months. Between 15 months and 2 years, that half-size jump takes two to three months. From ages 2 to 3, it slows to every three to four months, and from 3 to 5, roughly every four months.
In practical terms, this means you should remeasure every six to eight weeks for babies under 15 months, and every two to three months for toddlers. It’s easy to forget, so a calendar reminder helps. Shoes that fit perfectly in September can be too small by Thanksgiving.
Signs the Shoes Don’t Fit
Babies can’t tell you their shoes are too tight, so you have to watch for physical clues. Red marks or indentations on the skin after removing shoes are the most obvious sign. Blisters, especially on the toes or heel, point to friction from a shoe that’s either too small or too big. If your baby’s toes are jammed against the front of the shoe when you press down on the toe box, they’ve outgrown that pair.
Curled or overlapping toes during wear can also signal a fit problem. Some babies resist having shoes put on or try to pull them off constantly, which is sometimes just a preference for bare feet but can also indicate discomfort from a poor fit.
Why Shoe Choice Matters for Developing Feet
A baby’s foot bones are still largely cartilage, and they don’t fully harden until the teenage years. That soft, malleable structure means external pressure from tight or rigid shoes can physically alter how the foot develops. Research has shown that footwear design can influence arch development, gait mechanics, and even susceptibility to conditions like flat feet.
The most consistent recommendation across pediatric footwear guidelines is flexibility. Thirteen of fourteen studies and guidelines reviewed in a recent scoping review recommended that children’s shoes be flexible, particularly for kids under four. Flexible soles mimic the pressure distribution of walking barefoot, which is the ideal condition for developing feet. One study found that excessive cushioning in infant shoes actually altered how early walkers moved, suggesting that more padding isn’t always better. The goal is a shoe that protects the foot from the ground without restricting its natural movement.
For babies who aren’t walking yet, shoes are really just for warmth and protection. Soft-soled booties or socks with grip are plenty. Once your child starts walking, a lightweight shoe with a flexible sole and a secure closure (like velcro) supports healthy development without getting in the way.