Measure under arms around the fullest part of the chest. Be sure to keep tape level across back and comfortably loose.
Measure around natural waist with a measuring tape.
The sizing chart is approximate.
Small: Sleeve Length (8-3/4) Chest Width (18)
Medium: Sleeve Length (9) Chest Width (20)
Large: Sleeve Length (9-1/4) Chest Width (22)
Extra Large: (9-1/2) Chest Width (24)