Put on a well-fitting shirt or jacket
Stand straight with your arms relaxed at your sides
Measure from the center back of your neck to the shoulder point
Continue measuring down the outside of your arm to the wrist bone
Keep the tape measure straight and snug, not tight
If measuring a shirt, stop at the desired cuff length
If measuring a jacket, measure to where you want the sleeve to end
Record the measurement in inches or centimeters
Repeat on the other arm if you want to check for differences