Wear a thin shirt or dress shirt
Stand naturally with your arms relaxed
Measure chest around the fullest part, under the arms
Measure shoulders from one shoulder point to the other
Measure sleeve length from shoulder seam to wrist bone
Measure jacket length from the base of the neck to the desired hem
Measure waist around the narrowest part of your torso
Measure neck if needed for collar fit
Measure across the back for upper body width
Record all measurements in inches or centimeters
Compare your measurements to the brand’s size chart
Have someone else take the measurements if possible