Youth Sports Apparel Sizing Guide by Age Group

Youth sports apparel sizing trips up new sports families every season. A 9-year-old can be anywhere from youth small to adult small depending on their build. Below is the realistic sizing guide by age group, what the U-numbers (8U, 10U, 12U, 14U) mean in league context, and how to set up the shop so each family picks the right size without the coach collecting size forms.

Youth Cotton Tee Sizing

Age	Weight	Youth Size
4-5	35-45 lbs	Youth XS
6-7	45-60 lbs	Youth S
8-9	60-75 lbs	Youth M
10-12	75-100 lbs	Youth L
12-14	100-130 lbs	Youth XL or Adult XS/S

The Bear Grips Youth Airlume Cotton Athletic Tee runs true to size. Sizes can run slightly large at youth XS and slightly fitted at youth XL.

Performance Tee Sizing

The Sport-Tek Youth Moisture-Wicking Performance Tee runs slightly more fitted than the cotton version. For a snugger base-layer fit, order the same youth size as the player's cotton tee. For a roomier game-jersey-fit, size up one.

Youth Hoodie and Crewneck Sizing

The Gildan Youth Hoodie and Youth Crewneck Sweatshirt run roomy. Most players fit one size up from their tee size when ordering the hoodie. For example, a player in youth medium tees usually fits youth large hoodies cleanly with growth room.

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What 8U, 10U, 12U Mean in Youth Sports

The "U" stands for "Under." A player is eligible for an age group if they are under the age on the cutoff date. For example:

• 8U: Players under 8 years old as of the cutoff date.
• 10U: Players under 10 years old.
• 12U: Players under 12 years old.
• 14U: Players under 14 years old.

The cutoff date varies by sport and league (often May 1, August 31, or January 1). For apparel sizing, the actual player age and build matter more than the U-group, since a "10U" team can include both 8-year-olds and 9-year-olds with different sizes.

When To Size Up

• Growth spurt season. Boys and girls 11-14 often outgrow apparel mid-season. Size up if buying for a player who is mid-growth.
• Between-season storage. If the piece will be stored over summer for a fall season, size up one.
• Long-sleeve and outerwear. Size up half to one full size on hoodies, crewnecks, and long-sleeves to allow base-layer wear underneath.

How To Use the Sizing Chart in the Shop

Each product page in the shop shows the sizing chart. Parents browse, check their child's measurements, and order the right size. The coach or league admin never collects a single size form. If a family orders the wrong size, the family handles the exchange (rarely needed since the chart is in front of them).

Frequently Asked Questions

Are youth sizes consistent across brands?

Roughly. Bear Grips, Gildan, Sport-Tek, and Bella+Canvas all use standard youth size charts that align within an inch or two. The shop shows the exact chart per product.

What about kids who fall between sizes?

Size up for hoodies, crewnecks, and long-sleeves. Stay true to size on athletic-fit performance tees. The "between sizes" case usually resolves in favor of the larger size for growth allowance.

Does Pro Shops carry adult XS for older youth athletes?

Yes. Most adult blanks run XS to 3XL. Older youth athletes in the 12-14 range who outgrow youth XL often fit cleanly in adult XS or S.

Do you make 4XL or 5XL pieces for larger youth athletes?

Some adult blanks carry 4XL or 5XL. The product page shows live size availability. Not every product extends to 4XL.