What is a 4T?How 4T sizing compares across 43 kids' brands

A 4T is designed with 4-year-olds in mind, but age is only a rough guide. Because a 4T is built around height and build, plenty of children wear a 4T a year earlier or later than the label suggests. Checking your child's height against a specific brand's 4T is far more reliable than going by age alone.

Most brands cut a 4T for a toddler about 39–41" tall, but across brands it runs 37–43" — that full span is the honest answer. Height is what determines fit, so check your child's height against the specific brand's 4T rather than going by the age on the label.

Neither, reliably — a 4T is not standardized. Across these 43 brands it covers heights from 37 to 43", a spread of about 6 inches. It runs longer at Target Cat & Jack, Kohl's Jumping Beans, and Vineyard Vines Kids and shorter at Tommy Hilfiger Kids, Kyte Baby, and Magnetic Me, with most brands in between, so "big" or "small" only means anything next to a named brand.

No, and there is no industry standard that would make it so. Each brand sets its own 4T height range, which is why a 4T cannot be carried from one brand to the next: the size that fits in one brand can be short or roomy in another even though the label is identical.

At most brands the two cover nearly the same height — at The Children’s Place both are 38–41" — so the difference is the cut, not the size. A 4T is fuller through the seat for a child still in diapers or pull-ups; a straight 4 is leaner, for a potty-trained child. Out of diapers, the 4 usually fits better at the same height; if not, the 4T. Compare the height ranges, not the label.

After a 4T, most brands move to a 5T or a straight size 5. Sizing can shift noticeably at that step, so it's worth checking the next size's height range rather than assuming it picks up exactly where the 4T left off.

When your child's height is near the top of a brand's published 4T range, check that brand's a 5T or a straight size 5 before buying — the next size's range doesn't always pick up where 4T ends. We can't predict how long a garment lasts, so we point you to the boundary, not a guess.

Among the brands here, Target Cat & Jack cuts the longest 4T, fitting up to about 43 inches of height. That is about published height only — it says nothing about how long the garment itself lasts.