Quick answer: most 1-year-olds wear a US toddler size 4 or 5, which fits a foot about 4.5 to 5 inches long (11.5 to 12.7 cm). In Grookz sizing that's a Size 2 (7 to 12 months) if the foot measures 5 inches or under, and a Size 3 (13 to 18 months) if it's over. The only way to know which one is to measure the foot, which takes about a minute and is covered below.
Feet at this age vary more than most parents expect. Two healthy 12-month-olds can be a full size apart, and a baby who just turned one is often right on the line between two sizes. So treat every chart, including this one, as a starting point, and let the measurement make the final call.
12-month shoe size chart
This is the general US sizing most brands use for babies around their first birthday, alongside the Grookz age sizes, which run by foot length rather than by a number.
| Foot length | US toddler size | Typical age | Grookz size |
|---|---|---|---|
| 4.5 in / 11.4 cm | 4 | 9 to 12 months | Size 2 (7 to 12 months) |
| 4.75 in / 12.1 cm | 5 | 12 to 15 months | Size 2 up to 5 in, then Size 3 |
| 5.1 in / 13 cm | 6 | 15 to 18 months | Size 3 (13 to 18 months) |
| 5.5 in / 14 cm | 7 | 18 to 24 months | Size 3 up to 5.5 in, then Size 4 |
A few things worth knowing about that table. US sizes for babies and toddlers don't line up neatly with age, because the number tracks foot length and feet grow at their own pace. A 1-year-old who started walking early will often be in a 5 or 6. A smaller baby who's still cruising may be comfortable in a 4 for a few more months. Neither is a problem.
How to measure a 1-year-old's foot
Toddlers don't hold still, so the trick is to measure while they're standing and distracted. Standing matters because feet spread out under weight, and a foot measured on a lap can come out a quarter inch short.
- Put a sheet of paper on a hard floor and stand your child on it, holding their hands for balance.
- Mark the back of the heel and the tip of the longest toe. The longest toe isn't always the big toe.
- Measure the distance between the marks in inches or centimeters.
- Do the other foot. Most kids have one foot slightly bigger. Size to the bigger one.
- Add about half an inch (1.3 cm) of growing room when choosing a shoe size. For sock shoes, which stretch, a thumb's width of room at the toe is plenty.
If you'd rather skip the math, the free size finder takes the measurement and tells you which Grookz size to order. The full size chart covers every age from newborn through 3 years.
Why 12 months is the hardest age to size
Three things happen at once around the first birthday. Many babies start walking, which changes how a shoe needs to fit and makes a non-slip sole matter for the first time. Feet are still growing fast, roughly half a size every two to three months, so a pair bought in September can be tight by Thanksgiving. And a 12-month-old sits right at the boundary of most size ranges, including ours, which is why we list Size 2 as 7 to 12 months and Size 3 as 13 to 18 months.
The practical rule: if your child is turning one this month and the foot measures close to 5 inches, buy the Size 3. They'll grow into any extra room within weeks, and a slightly roomy sock shoe stays on fine because the knit grips the ankle. A too-small shoe is the one that causes trouble, because toes curl and new walkers lose their balance.
Signs the current pair is too small
- Red marks on the toes or top of the foot after taking shoes off
- Toes pressed against the end, or curling under when standing
- A sock shoe that's suddenly hard to pull over the heel
- Your child pulling at their shoes more than usual, or refusing them. (If that's new, our post on why babies hate shoes covers the other causes.)
- More than two months since you last checked the fit
What kind of shoe does a 1-year-old need?
Indoors, a 1-year-old who's learning to walk does best barefoot or in something that behaves like bare feet: a thin, flexible sole they can feel the floor through, and a non-slip surface on hardwood and tile. That's exactly what a sock shoe is. The knit upper stretches over the foot like a sock, and the rubber sole gives traction without the stiffness of a hard-soled shoe.
Outdoors on sidewalks and playgrounds, once walking is steady, a slightly firmer sole with a mesh upper holds up better. That's where our first walker shoes come in. For most 12-month-olds, though, a pair of sock shoes covers daycare, the house, the stroller, and grandma's tile floors.
Our 7 to 12 months collection and 13 to 18 months collection are sorted by the two sizes a 1-year-old is most likely to wear. The Adventure line is the plain, solid-color pair most parents start with.
How often should you re-measure?
Every two months between 12 and 24 months. Growth isn't steady, so you might see no change for six weeks and then a jump. Measuring takes a minute, and it's cheaper than replacing a pair that was outgrown before it wore out. Keep the paper from the last measurement and compare.
Frequently asked questions
What size shoe does a 12-month-old wear?
Usually a US toddler 4 or 5, for a foot around 4.5 to 5 inches. In Grookz sizing, Size 2 up to 5 inches and Size 3 above that.
Is a size 4 or size 5 right for a 1-year-old?
Measure the foot. Under 4.6 inches, a 4 fits. Between 4.6 and 4.9 inches, a 5 gives room to grow. At 5 inches or more, go to a 6.
Should I buy a size up for a 1-year-old?
Buy for the measured foot plus about half an inch of room. Buying two sizes up to save money backfires: shoes that are too long trip new walkers.
Do 1-year-olds need hard-soled shoes?
No. Soft, flexible soles are better for new walkers. Save firmer soles for steady walkers who spend real time outdoors.
How much do a baby's feet grow between 12 and 24 months?
About an inch over the year for most children, which is roughly three to four US sizes. Check the fit every two months.
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