Most 8 year olds wear a youth small or youth medium in t-shirts. The right size depends on the child's chest measurement and height, not just their age. An 8 year old who is 4 foot 2 and lean fits youth small. An 8 year old who is 4 foot 6 and stocky needs youth medium.
Shirt Sizes for 8 Year Olds by Brand
| Brand | Youth Small Chest (in) | Youth Medium Chest (in) | Best Fit for Average 8yr |
|---|---|---|---|
| Gildan | 28-30 | 30-32 | Youth Small |
| Bella+Canvas | 26-28 | 28-30 | Youth Medium |
| Comfort Colors | 28-30 | 30-32 | Youth Small |
| Next Level | 26-28 | 28-30 | Youth Medium |
| Hanes | 28-30 | 30-32 | Youth Small |
The brand matters here more than most parents realize. An average 8 year old with a 28-inch chest fits youth small in Gildan but needs youth medium in Bella+Canvas because Bella+Canvas runs about 2 inches narrower at the same labeled size. Always check the specific brand's chart.
Who Fits What at Age 8
The average 8 year old in the United States is about 4 foot 2 and weighs around 55 pounds. That puts most of them at the upper end of youth small or the lower end of youth medium depending on the brand.
Here is a breakdown by body type:
Lean build (4'0" to 4'4", under 50 lbs): Youth small in Gildan, Hanes, or Comfort Colors. Youth medium in Bella+Canvas or Next Level. The boxy brands will have enough room without swimming on a thin frame.
Average build (4'0" to 4'5", 50 to 65 lbs): Youth small in boxy brands, youth medium in slim brands. This is the most common 8 year old order.
Stocky or athletic build (4'2" to 4'6", over 65 lbs): Youth medium across the board. The extra chest width prevents the shirt from pulling tight when they raise their arms.
Which Size to Order
If you cannot measure the child, youth small is the safest bet for an 8 year old in Gildan or Hanes. It fits the widest range of builds at that age without being too tight or too baggy.
If you are ordering for a team of 8 year olds, expect the size split to run about 60/40 between youth small and youth medium. A few smaller kids might still be in youth XS, especially early in the school year. Our guide on sizing custom shirts for youth sports teams covers the breakdown.
If the shirt is a gift, size up to youth medium. Kids at 8 grow fast, and a shirt with room to grow gets six more months of wear.
When to Move to Youth Medium
If youth small is getting snug across the chest or the body length is riding above the waist, it is time for youth medium. Youth medium adds about 2 inches in the chest and 1 to 2 inches in body length depending on the brand.
Most kids transition from youth small to youth medium somewhere between ages 8 and 10. For a detailed look at the next size up, check our What Size Is Youth Medium guide and our What Size Is Youth Large guide.
What size shirt does an 8 year old wear?
Most 8 year olds wear youth small in Gildan, Hanes, and Comfort Colors. In Bella+Canvas and Next Level, which run slimmer, they typically need youth medium. The best way to determine the right size is to measure across the chest from armpit to armpit and double it, then compare to the brand's size chart.
Is an 8 year old youth small or medium?
It depends on the brand and the child's build. An average 8 year old with a 28-inch chest fits youth small in boxy brands like Gildan and Hanes. In slim-fit brands like Bella+Canvas, that same child needs youth medium. Larger or athletic 8 year olds should go with youth medium across all brands.
What size is an 8 year old in adult shirts?
An 8 year old is not ready for adult sizing. Adult XS starts at 30 to 32 inches in the chest with a body length designed for adult proportions. Youth small or medium is the correct size range for an 8 year old. The transition to adult sizing does not typically happen until ages 14 to 16. See our Is Youth XL the Same as Adult Small guide for when that transition makes sense.
Related Sizing Guides
- What Size Shirt for a 6 Year Old?
- What Size Shirt for a 10 Year Old?
- What Size Shirt for a 12 Year Old?
- What Size Is Youth Small?
- What Size Is Youth Medium?
- Gildan Youth Sizing Guide
- Comfort Colors Youth Sizing Guide
- How to Size Custom Shirts for Youth Sports Teams
Ordering Shirts for a Group of 8 Year Olds?
If you are a coach, parent, or event organizer ordering shirts for a group of 8 year olds, we will help you get the sizing right so every kid gets a shirt that fits. Start your order here and let us know the age range. We will recommend the right size split for your group.