SHIRT MEASUREMENTS: (measurements are approximate) SMALL: COLLAR TO SEAM: 23 inch / 58.4 cm ARMPIT TO ARMPIT: 21 inch / 53.3 cm MEDIUM: COLLAR TO SEAM: 24 inch / 61 cm ARMPIT TO ARMPIT: 21.5 inch / 54.6 cm LARGE: COLLAR TO SEAM: 25.25 inch / 64.1 cm ARMPIT TO ARMPIT: 22.5 inch / 57.2 cm XL: COLLAR TO SEAM: 26.25 inch / 66.7 cm ARMPIT TO ARMPIT: 24 inch / 61 cm