Armhole explained, the opening your sleeve sits in

Short answer: An armhole is the opening in a t-shirt where the sleeve is attached, or where your arm comes through. The size and position of the armhole decide how freely you can move your arms and how the shirt sits over your shoulders and upper arms.

What an armhole is

An armhole is the round opening in the body of the shirt that the sleeve is sewn into. On a sleeveless top it is the opening you put your arm through, and on a t-shirt it is the seam between body and sleeve. The word is used for both the opening and the seam that runs around it.

What the armhole looks like on a t-shirt

The seam starts at the shoulder seam, runs down under the underarm and back up in a soft curve. A high armhole sits close to the underarm, while a low armhole gives more room. If you want to compare how different cuts place this seam, look at bamboo T-shirts for men and see how each one is cut.

High or low armhole

A high armhole looks tidy, and the shirt lifts less when you raise your arms. A low armhole gives more freedom to move and a relaxed look, but the fabric can gather under the arm. The right choice depends on how you move and whether you wear the shirt alone or under something else.

How the armhole feels when you move

When you lift your arm, a tight armhole pulls along the whole side of the shirt, and the edge of the fabric can rub against the skin. An armhole with a little room follows your movement, so you hardly notice it. Reach forward and up when you try on a shirt.

The seam around the armhole

The seam sits close to a sensitive part of the body, so it should be flat and even. Feel whether it sticks out or presses when you wear the shirt, and check that it lies neatly without twisting. A clean seam makes a big difference to comfort over many hours.

Shoulder seam and armhole belong together

The shoulder seam should sit at the edge of the shoulder, so the armhole can sit as intended. If the seam hangs down over the upper arm, the armhole becomes too large and too low, and the sleeve droops. If it sits too high, the shirt pulls when you reach forward.

How to check the armhole in the mirror

Stand in front of a mirror and raise your arms a little. See whether the hem follows without pulling at the neck or lifting over the stomach, and feel whether the edge rubs. The same goes for other clothes, including socks for men, where the fit is felt after only a few steps.

Washing and care affect the fit

After some washes a t-shirt can change shape if it is dried on high heat, and the armhole may become a little smaller or more uneven. Wash as the label says and let the shirt dry flat or on a hanger, so the seams are not pulled out of line. The same applies to bamboo boxer briefs, where seams and edges can also lose their shape.

Frequently asked questions

What does armhole mean?

An armhole is the opening in a garment where the arm comes through or where the sleeve is attached. Its size decides how freely you can move in the shirt.

Should an armhole be tight or loose?

It should be snug enough that the shirt does not hang, but not so tight that it pulls when you lift your arms. Move around before you choose a size.

Can an armhole rub against the skin?

Yes, if the seam is too hard or the opening is too small. Choose a size with a little room and check that the seam lies flat, so it neither presses nor rubs.