Sizing and fit
What size T-shirt fits a 3-year-old?
Short answer
A 3-year-old normally takes 3T. Measured flat, a 3T shirt is 13 inches across the chest and 16½ inches long, and both toddler blanks we checked agree on that exactly. The T stands for toddler, and those patterns are cut wider through the hips and shorter in the body than youth sizes — which matters if the child is still in nappies.
Toddler sizing (2T, 3T, 4T) and youth sizing (XS 4/5 upward) overlap at the top of the range but are cut differently. Toddler patterns allow room for a nappy and have a wider neck opening for getting the garment over a large head — a genuine design consideration at this age, and the reason a 4T and a youth XS fit differently despite covering similar ages.
If a three-year-old is out of nappies and tall, 4T often works better than 3T for length, and will last longer. If they are still in nappies, stay with 3T regardless of height.
Neck openings are worth checking specifically. Some licensed ranges use a standard youth neck on toddler sizes to save on tooling, and those are the shirts that end up in the drawer because the child objects to them going on.
| US size | Label | Cut | Best for |
|---|---|---|---|
| 3T | toddler 3 | Wider hip, shorter body, wide neck | Most 3-year-olds |
| 4T | toddler 4 | Same cut, one inch wider and longer | Tall or broad for three |
| XS | youth 4/5 | Narrower hip, longer body | Out of nappies and slim |
What 3T measures
Chest is measured flat across the shirt, so double it to get the way round. Body length runs from the high point of the shoulder to the hem.
3T
Both toddler blanks measure identically at every size from 2T to 5T, which makes toddler sizing far more predictable than youth sizing.
| Blank | Labelled | Chest, flat | Body length |
|---|---|---|---|
| Rabbit Skins 3321 | 3T | 13 in | 16½ in |
| Bella+Canvas 3001T | 3T | 13 in | 16½ in |
Across these blanks, every one measures 13 in across the chest, and all are 16½ in long.
4T, if you are sizing up
| Blank | Labelled | Chest, flat | Body length |
|---|---|---|---|
| Rabbit Skins 3321 | 4T | 14 in | 17½ in |
| Bella+Canvas 3001T | 4T | 14 in | 17½ in |
Across these blanks, every one measures 14 in across the chest, and all are 17½ in long.
Where these come from: each manufacturer's own published spec sheet, read on September 29, 2026 — Rabbit Skins 3321, Bella+Canvas 3001T. Manufacturers allow a tolerance on every measurement, so an individual shirt can differ by up to an inch. We have not measured these shirts ourselves.
More detail: US T-Shirt Size Guide: Toddler to 3XL covers this subject in full.
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