Birthday Shirt Sizing and Fit Guide for Group, Family, and Adult Orders

Sizing is where most birthday shirt group orders go wrong, not the design. A shirt that fits the birthday person perfectly can run big or small on a cousin, a coworker, or a party guest wearing the same labeled size in a different cut. Here is how to size a birthday shirt order correctly, whether it is one shirt or forty.

Unisex vs Fitted Cuts: Why the Same Size Fits Differently

• Unisex tees (like the Airlume Cotton Athletic Tee) run boxier through the body and are the safest default for a group where fits are unknown.
• Fitted women's cuts (like the Women's Favorite Tee or Women's Premium Cotton Tee) run narrower through the waist. Someone who wears a medium in unisex often wears a large in a fitted women's cut.
• Racerback tanks and cropped styles run smaller still. Check the specific product size chart rather than guessing from a tee size.

Youth vs Adult Sizing for a Family Birthday Order

Age range	Typical size	Product line
Toddler to age 6	Youth XS-S	Youth Airlume Cotton Athletic Tee
Age 7-12	Youth M-L	Youth Airlume Cotton Athletic Tee, Youth Hoodie
Teen (13+)	Adult XS-S	Most adult product lines fit from here
Adult	Adult S-3XL	Full adult catalog range

Teenagers usually fit better in adult extra small or small rather than the largest youth size, especially for a fitted cut.

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Sizing a Group Order Without Guessing

1. Send a size-collection link or form to every guest before ordering. Collect their usual size in the specific product being ordered, not just "small, medium, large" in general.
2. Order one sample piece first for an unfamiliar brand or cut. Confirm fit in hand before committing to a 20-plus piece order.
3. Round up for anyone between sizes. A slightly loose shirt photographs better than a tight one.
4. Keep a small buffer of 1-2 extra shirts in the most common size. Covers a late guest addition or a miscounted head.

Plus Size Range for Adult Birthday Orders

Most adult tee and hoodie lines run through at least 3XL, covering the majority of adult body types in a single group order without needing a separate size chart for plus size guests. Check the specific product page for the exact top size available, since range varies slightly by brand and cut.

What to Do if a Size Comes in Wrong

If a shirt in a group order does not fit once it arrives, reach out through the order support process rather than reprinting from scratch. Catching a size issue on one piece is far cheaper than resizing a whole group order after the fact, which is exactly why a sample order matters for anything larger than a handful of shirts.

Frequently Asked Questions

Should I order unisex or fitted for a birthday group order?

Unisex is the safer default when sizes are unknown across a mixed group. Fitted cuts work well when each guest has confirmed their usual size in that specific style first.

What age can wear an adult small?

Most teenagers from around age 13 fit an adult extra small or small, depending on build. Check the specific size chart since it varies by product.

How early should I collect sizes for a group birthday order?

At least 10 to 14 days before the party, which leaves time to place the order, get it printed, and still have a buffer if a guest is added late.

What is the largest size available for adult birthday shirts?

Most adult tee and hoodie lines go up to at least 3XL. Check the individual product page for the exact top size.