Sizing and fit
What size T-shirt fits a 10-year-old?
Short answer
A 10-year-old usually takes the size labelled 10/12 — but check which letter that is, because it is youth medium in Gildan, Hanes and Bella+Canvas and youth large in Next Level. Measured flat, youth medium runs 16¼ to 18 inches across the chest and 22 to 23½ inches long. Where a design is only made in adult sizes, an adult XS is a reasonable substitute.
Ten is the age at which the youth and adult ranges begin to meet. Youth large and adult XS are frequently cut from patterns with a similar chest, but the youth version is shorter in the body and narrower at the shoulder. For a child who is tall and slim, adult XS often fits better; for one who is broad, youth large usually does.
It is also the point where children commonly start preferring adult-cut shirts for the way they hang, regardless of measurement. That is a preference rather than a fit question, but it is worth asking before ordering.
Licensed ranges thin out above youth XL, so if a child is at the top of the youth range and the design matters more than the exact fit, moving to adult sizing widens the available choice considerably.
| Label | Letter size | Cut | Best for |
|---|---|---|---|
| 10/12 | M in Gildan, Hanes, Bella+Canvas | Youth medium | Most 10-year-olds |
| 10/12 | L in Next Level | Youth large | Same garment, different letter |
| 14/16 | L in most brands | One size up | Tall or broad for ten |
Youth M and L, measured
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.
Youth M (10/12)
| Blank | Labelled | Chest, flat | Body length |
|---|---|---|---|
| Gildan 2000B | M (10-12) | 18 in | 23½ in |
| Gildan 64000B | M (10-12) | 17 in | 22 in |
| Hanes 5450 | M | 17 in | 23 in |
| Next Level 3310 | M (8) | 17 in | 22 in |
| Bella+Canvas 3001Y | M (10-12) | 16¼ in | 22⅛ in |
Across these blanks, the chest ranges from 16¼ to 18 in across — 1¾ in of difference, or 3½ in the whole way round, and the body runs 22 to 23½ in long.
Youth L (14/16)
| Blank | Labelled | Chest, flat | Body length |
|---|---|---|---|
| Gildan 2000B | L (14-16) | 19 in | 25 in |
| Gildan 64000B | L (14-16) | 18 in | 23½ in |
| Hanes 5450 | L | 18 in | 25 in |
| Next Level 3310 | L (10/12) | 18½ in | 23½ in |
| Bella+Canvas 3001Y | L (14-16) | 17¼ in | 23⅜ in |
Across these blanks, the chest ranges from 17¼ to 19 in across — 1¾ in of difference, or 3½ in the whole way round, and the body runs 23⅜ to 25 in long.
Where these come from: each manufacturer's own published spec sheet, read on September 29, 2026 — Gildan 2000B, Gildan 64000B, Hanes 5450, Next Level 3310, Bella+Canvas 3001Y. 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.
Related questions people ask
What adult size fits a 10-year-old?
Adult XS, at about 31–34 inches in the chest, is the usual substitute when a design is not made in youth sizes. It runs longer in the body than youth L, which some children dislike.
Is youth L the same as youth 10?
Effectively yes. Youth L is normally labelled 10/12, meaning it is cut for ages 10 to 12. The numbers on youth labels are ages, not chest measurements.
Shirts in these sizes
- Youth shirts (M, L, XL)
- Video game shirts — popular at this age
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