Sizes can vary from 1-3 centimeters because they are measured by hand. 1inch=2.54cm
Sleeve: Measure from the middle of the back of the neck, out to the shoulder, and down to the wrist.
Chest/Bust: Measure circumference around the widest part chest/best
Waist: Measure natural waist where pants sit (think regular rise pants).
Hips: Stand straight and measure around the largest circumference at hips.