How and What to Measure
Make sure you son is not wearing bulky clothes and use a tape measure to follow the advice below.
Stand without shoes and feet together with back against a wall. Measure from the top of the head to the floor.
Measure around the base of the neck, inserting two fingers between the neck and tape to allow growth.
Place tape close to underarms, measure chest at fullest point with arms by the side.
Measure around the natural waistline or measure across an existing pair of trousers and multiply by two.
Measure with shoes on, from the top of the inside leg (crouch) to the bottom of leg, where you would like the trouser length to finish.