How to Measure a Shirt: Sleeve Width
Lay the shirt on its back. Spread the shirt sleeve out flat such that the seam along the bottom of the sleeve is where the sleeve is folded. Place one end of the measuring tape on the bottom edge of the sleeve, an inch from the armpit. Measure up to the top of the sleeve such that the measuring tape is perpendicular to the top folded edge of the sleeve. Do not stretch the sleeve but be sure it is spread out flat.
Standard Shrinkage Allowance:
Proper Cloth does not add a standard shrinkage allowance to the Sleeve Width dimension.
Extra Shrinkage Allowance:
For a shirt with an Extra Shrinkage allowance of 2% (for example), a shirt ordered with a 9.0” Sleeve Width will measure (9.0”) * (100% + 2%), amounting to 9.2” out of the box.
While we do our best to sew each garment precisely to its specification every time, hand sewing and different fabric types naturally result in small variations. We consider a tolerance of +0.1875″ to -0.1875″ acceptable for the Sleeve Width dimension.