The Tuxedo Dress Shirt

Measure body, not shirt. 

Measure the circumference of your neck with two fingers between your neck and the measuring tape for a comfortable fit. Make sure that the angle of the measuring tape follows the direction a collar would naturally sit on your neck and falls under the Adam's apple. 

With your shirt still buttoned, flip it over so it faces down. Start by measuring from the center of the neck at the base of the collar seam. From that point, extend the measuring tape along the shoulder seam, then down the sleeve all the way to the end of the cuff. This is your sleeve length measurement. No need to add for shrinkage - we've done that for you. If you are between sizes, go with the longer of your possible measurements.

Make sure your shirt is buttoned and lay it flat. Measure from the armhole at the side seam across to the other side. Multiply that number by 2 to get the shirt chest measurement.

With your shirt laid flat, measure across the side seam of the the slimmest part of the shirt (which should be about halfway between the armhole and the hem). Multiply that number by 2 to get the shirt waist measurement.

With your shirt facing up and laid flat, measure down the center of the front of the shirt. Start where the collar meets the placket (where the buttons are sewn on) and measure down to the bottom seam. That length is your front body length measurement.

Lay your shirt flat, facing down. Start from the center of the back of the collar, where the collar band meets the neck seam. Measure down the back center of the shirt all the way to the bottom of the hem. That measurement is your shirt back body length.