AlpacaPirate

A Length

Place the end of the tape beside the collar at the top of the tee (Highest Point Shoulder). Pull the tape measure to the bottom of the shirt.

B Width

Place the end of the tape at the seam under the sleeve and pull the tape measure across the shirt to the seam under the opposite sleeve.

C Sleeve length

Place one end of the tape at the top of the set-in sleeve, then pull the tape down until you reach the hem of the sleeve.