Most 13 year olds wear youth XL, with taller or broader kids moving into adult small. At 13, kids enter the first year of the youth-to-adult transition, a year earlier than most parents expect, so the right size depends on chest measurement and height, not just age.
Shirt Sizes for 13 Year Olds by Brand
| Brand | Youth XL Chest (in) | Adult Small Chest (in) | Best Fit for Average 13yr |
|---|---|---|---|
| Gildan | 34-36 | 34-36 | Youth XL |
| Bella+Canvas | 32-34 | 34-36 | Youth XL or Adult S |
| Comfort Colors | 34-36 | 36-38 | Youth XL |
| Next Level | 32-34 | 34-36 | Youth XL or Adult S |
| Hanes | 34-36 | 34-36 | Youth XL |
At 13, youth XL and adult small overlap in chest measurement in most brands but differ by about 3 inches of body length. Youth XL runs 24-25 inches long. Adult small runs 27-28 inches long. A 13 year old who is shorter and leaner fits the shorter youth XL proportions better. A 13 year old who is taller or broader needs the extra length of adult small.
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Get a Free QuoteFor the exact conversion between the two sizes, see our what size is youth XL in adult guide and our youth XL size chart with complete measurements.
Who Fits What at Age 13
The average 13 year old in the United States is about 5 foot 2 and weighs around 100 pounds. That puts most of them squarely in youth XL, with the taller and heavier end of the age group starting to need adult small.
Lean build (4'11" to 5'3", under 95 lbs): Youth large in boxy brands, or youth XL in slim brands like Bella+Canvas and Next Level. Which one depends on the individual brand's chest measurement.
Average build (5'0" to 5'4", 95 to 115 lbs): Youth XL in most brands. This is the most common 13 year old order by far.
Taller or athletic build (5'3" to 5'7", over 115 lbs): Adult small. The transition rule is simple: if the chest measures over 36 inches or the kid is over 5 foot 6, go adult small.
The First Year of the Youth to Adult Transition
Thirteen is the age when the youth-to-adult transition actually starts, a year earlier than most parents plan for. Many parents assume this shift happens closer to 14 or 15, but the chest measurements show it beginning right at 13 for taller or broader kids.
Do not skip from youth large straight to adult small. Youth XL is the bridge size between the two, and jumping over it usually means either a shirt that is too tight in the chest or one that is far too long in the body. For the full walkthrough of this transition, see our youth XL to adult small transition guide.
Sizing for Team Orders With 13 Year Olds
Teams with 13 year olds typically need a mixed youth and adult order, since the roster splits between kids still in youth XL and kids who have already moved into adult small. A typical team of 15 at this age breaks down roughly: 4 youth large, 7 youth XL, 4 adult small.
Do not guess on a roster like this. Run a measurement check or a try-on session before finalizing sizes. For the full team ordering formula, see our how many shirts to order guide.
What size shirt does a 13 year old wear?
Most 13 year olds wear youth XL. Taller or broader 13 year olds, especially over 5 foot 6 or with a chest over 36 inches, need adult small instead. In slim brands like Bella+Canvas, more 13 year olds fall into the adult small range than in boxy brands like Gildan.
Is a 13 year old youth XL or adult small?
It depends on height and chest measurement. An average 13 year old (5'2", 100 lbs) fits youth XL in most brands. Youth XL and adult small overlap in chest width but differ by about 3 inches of body length. Youth XL suits shorter, leaner 13 year olds. Adult small suits taller or broader ones.
Does a 13 year old wear youth or adult sizes?
Both, depending on the individual. Thirteen is the first year of the youth-to-adult transition, earlier than most parents expect. Most 13 year olds are still in youth XL, but the taller and heavier end of the age group has already moved into adult small. Do not skip from youth large to adult small. Youth XL is the proper bridge size.
Related Sizing Guides
- What Size Shirt for a 12 Year Old?
- What Size Shirt for a 14 Year Old?
- What Size Shirt for an 11 Year Old?
- Youth Size to Kids Size Conversion Chart
- What Size Is Youth XL in Adult?
- Youth XL Size Chart: Complete Measurements
- Youth XL to Adult Small Transition Guide
- How Many Shirts to Order for a Team
Ordering Shirts for 13 Year Olds?
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