Kids shoe sizes, and why 1 is bigger than 13

The US children's scale counts up to 13 and then starts again at 1. A child who has outgrown a 13 needs a 1, not a 12. It is the single most common ordering mistake in children's footwear and it has nothing to do with you.

How the scale actually runs

There are two children's ranges sharing one set of numbers. Toddler and little kid sizes run from about 4 up to 13. When the foot outgrows 13, the big kid range restarts at 1 and runs to about 7, at which point it meets the adult scale. So the order is 12, 12.5, 13, 13.5, then 1, 1.5, 2.

Some retailers write it as 13C and 1Y to keep them apart, some do not, and the same shoe can be listed both ways on the same marketplace. If a listing simply says "1", check the length in millimetres before assuming which 1 it means. That is the only unambiguous number on the page.

Foot length to US size

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Kids' sizes

Kids' 10up to 171 mm (17.1 cm)
Kids' 10.5up to 175 mm (17.5 cm)
Kids' 11up to 181 mm (18.1 cm)
Kids' 11.5up to 184 mm (18.4 cm)
Kids' 12up to 191 mm (19.1 cm)
Kids' 12.5up to 194 mm (19.4 cm)
Kids' 13up to 197 mm (19.7 cm)
Kids' 13.5up to 203 mm (20.3 cm)
Kids' 1up to 206 mm (20.6 cm)
Kids' 1.5up to 210 mm (21.0 cm)
Kids' 2up to 216 mm (21.6 cm)
Kids' 2.5up to 219 mm (21.9 cm)
Kids' 3up to 222 mm (22.2 cm)
Kids' 3.5up to 229 mm (22.9 cm)
Kids' 4up to 232 mm (23.2 cm)
Kids' 4.5up to 235 mm (23.5 cm)
Kids' 5up to 241 mm (24.1 cm)
Kids' 5.5up to 244 mm (24.4 cm)
Kids' 6up to 248 mm (24.8 cm)
Kids' 7up to 254 mm (25.4 cm)

Measure more often than feels necessary

Under-threes can go up a size every couple of months. Between three and six it slows to roughly a size every four or five months, and it keeps slowing from there. Growth is not steady, though, so a schedule beats an estimate: check every eight to ten weeks until school age.

Children do not reliably report that shoes hurt. Small feet are soft enough to deform into a shoe that is too short rather than complain about it, and a curled toe or a red mark across the top of the foot is the more honest signal.

Measuring a small foot without an argument

Wide feet are the normal case in childhood

Children's feet are proportionally wider than adults', with a fan-shaped forefoot and a fat pad that has not yet thinned out. Most mass-market kids shoes are built on adult-shaped lasts scaled down, which is why so many toddlers end up with a strap dug into the top of the foot.

The wide toe box sneaker and the wide slip-on here are on kids-specific wide lasts. The web-print and lightning sneakers are standard width, so if you already know your child needs room across the forefoot, those two are the wrong shelf.

Closures a child can work alone

Independence at the door is worth more than most people expect. A hook-and-loop strap is the easiest thing for a three-year-old to operate and adjusts across a chubby instep, which laces at that age do badly. A bungee cord with a toggle is the next step up: it pulls tight one-handed, stays put, and skips the two years between wanting to do it yourself and being able to tie a bow.

Elastic slip-ons are the fastest of all and the least adjustable. They suit a preschool where shoes come off and go on repeatedly, and they suit a narrow foot poorly, because there is nothing to tighten.

The barefoot question, honestly

Zero-drop, flexible-soled shoes let a foot move closer to the way it moves unshod, and the argument for them in early childhood is reasonable: the foot is still forming, and a stiff shoe does some of the work the foot should be doing itself.

The trade-off is real too. There is very little between the sole and the ground, so cold, wet and sharp surfaces all come through, and a child who needs ankle support or a fastening they can tighten is better off in the strapped sneaker. The kids slip-on in this range is the barefoot-style option; the wide sneaker is the conventional one. Neither is the right answer for every child.