Neck Size: Take a shirt that fits you well, lay the collar flat and measure from the center of collar button to far end of collar button-hole. The measurement in inches is your neck size.

Chest/Bust: Measure around the fullest part of your chest, under arms and across shoulder blades.

Sleeve length: Bend elbow up, measure from center of neck (back) to elbow and up to wrist.

SHIRTS / JACKETS
SIZE	NECK	CHEST	WAIST	SLEEVE
S	14" - 14½"	34" - 36"	28" - 30"	32½" - 33"
M	15" - 15½"	38" - 40"	32" - 34"	33½" - 34"
L	16" - 16½"	42" - 44"	36" - 38"	34½" - 35"
XL	17" - 17½"	46" - 48"	40" - 42"	35" - 35½"
2X	18" - 18½"	50" - 52"	44" - 46"	35½" - 36"
3X	19" - 19½"	54" - 56"	50" - 52"	36½" - 37"

Geox