Lay a well-fitting dress shirt flat on a smooth surface
Button the shirt fully and smooth out wrinkles
Measure the collar by placing the tape around the inside of the collar from button to buttonhole
Measure the neck by wrapping the tape around the base of the neck, leaving room for one finger
Measure the chest across the shirt from armpit to armpit and double the measurement
Measure the waist across the shirt at the narrowest point and double the measurement
Measure the shoulders from shoulder seam to shoulder seam across the back
Measure the sleeve length from the center back of the neck to the shoulder seam and down to the cuff
Measure the upper sleeve width across the fullest part of the sleeve and double it if needed
Measure the shirt length from the highest point of the shoulder near the collar to the bottom hem
Measure the cuff width across the cuff when buttoned
Measure the armhole by tracing around the sleeve opening if needed
Record all measurements in inches or centimeters consistently