Here are some steps you have to follow to measure a jacket with the help of measurement tape.
1) Chest width: Measure from the bottom of one armhole across the chest to the bottom of the opposite armhole. (Chest Measurement)
2) Shoulder to sleeve: Measure from the tip of the shoulder down to the bottom of the sleeve with the help of a measuring tape. (Sleeves Measurement)
3) Waist Width: Place the measuring tape where the natural waist would fall, usually a bit lower than halfway down the jacket, and measure from one side of the jacket across to the other. (Waist Measurement)
4) Shoulder to Shoulder: Place the measuring tape at the corner of one shoulder and pull across to the other shoulder. This is an important measurement as some people typically wear the same size but have different shoulder widths (Shoulder Measurement)
