Wear a thin shirt and stand naturally with your arms relaxed
Measure chest around the fullest part, under the arms and across the shoulder blades
Measure shoulders from one shoulder point to the other across the back
Measure sleeve length from the shoulder seam point to the wrist bone with the arm slightly bent
Measure neck by wrapping the tape around the base of the neck where a collar sits
Measure waist at the natural waistline, usually around the navel or narrowest part
Measure jacket length from the base of the neck at the center back down to the desired hem point
Measure across the upper back from one armhole seam point to the other if needed
Compare all measurements with the suit brand’s size chart
Have someone else take the measurements for better accuracy