Measurement from underarm to underarm then doubled for correct sizing. You can measure this by wrapping the tape around the fullest part of your chest.
Sleeve
Measurement from the shoulder to the cuff.
Raglan Sleeve
Measurement from the top of the neckline to the end of the sleeve cuff. Some garments do not have a shoulder seam due to a ‘Raglan’ sleeve design, where the shoulder has a seamless curve. As there is no specific shoulder seam from which to measure the sleeve length, we measure from the top of the neckline to the end of the sleeve cuff to provide better accuracy.
Length
Measurement from the shoulder to the lowest point of the hemline on the garment.