How to buy a long-sleeve shirt
Clothing manufacturers use two sizing systems for long-sleeve shirts. Button-downs predominantly use: (1) the neck circumference and (2) the sleeve length. The neck circumference is measured where the collar sits. The sleeve length is measured from the base of the neck to the shirt’s cuff. On the other hand, T-shirts, polos, and some button-down shirts use the standard S-M-L-XL format.
All standard long-sleeve measurements follow the same basic principle. The shoulder usually has a circle-shaped seam which attaches the sleeve to the rest of the shirt. And if you ran a finger from your neck to your elbow, you would eventually notice a point where your shoulder stops running horizontally and your arm begins to run vertically. When a shirt fits well, the shoulder seam falls on that point.
If the seam is closer to your neck, the shirt’s shoulders are too narrow and your armpits are probably stuffed with fabric. If the seam droops toward your elbow, the sleeve will appear longer, but the rest of the shirt will billow around your torso. This is the error most tall men commit. They want longer sleeves so they get bigger shirts. But when manufacturers make a shirt’s shoulders wider, they also make the belly looser. The entire torso is widened. The shirt’s cuff may reach their wrist, but because the length came from the wider torso, the shirt fits loose around the belly.
Here’s what I recommend to get the best possible fit: First, go to a regular department store or open your closet. Bring a tap measure, since this is a research project. Momentarily disregarding sleeve length, try on shirts to find two measurements: (1) the most comfortable neck measurement and (2) the shoulder breadth. The neck measurement has been explained, but the shoulder breadth is where we start to deviate from conventional sizing. Try on shirts until the shoulder seam falls where it should: the point where your shoulder stops being horizontal, and your arm starts being vertical. Take the shirt off and lay it flat. Use the tape measure to measure the shirt seam-to seam. You now have two of three necessary measurements.
The third measurement is the sleeve itself. That shirt with well-fitting shoulders but short sleeves—put it on. We’ll call it “the reference shirt.” Measure the distance between the reference shirt’s cuff and the spot you’d prefer the sleeve to fall, the “shortcoming” length. Then take the reference shirt back off, measure the sleeve as-is, and add the reference shirt’s sleeve length to the shortcoming. It may seem convoluted, but in my experience, this yields a more accurate result than tape-measuring your arms with no reference shirt.
Everyone knows where they want their shirt cuffs to fall. But for standard-sized shirts, the sleeves simply do not fit tall men’s arms. All too often, tall men will compensate by buying an extraordinarily wide shirt. Don’t do that. Get measurements on your shoulder breadth, neck, and sleeve, and compare those measurements to those posted by other users on TallThreads. And if you’re the first to discover a shirt’s sizing, you have a great opportunity to save others a headache.