How to Measure
Before you start — three things on the table
A cloth tape
Flexible, marked in inches and centimetres. A phone charging cable is not a substitute.
A fitted layer
Measure over a snug t-shirt and slim trousers — not baggy, not bulky.
A second pair of hands
A friend gets you a straighter back and cleaner shoulder. Alone works too — stand by a mirror.
Watch it done
Two short walkthroughs — pick the one that matches you and measure along.