Use a tape measure. For more accurate measurements, measure directly on the body. Keep a pen and paper ready and write down the measurements.
A. Chest
Lift arms and measure around the largest part of the chest.
B. Waist
Measure around the waist at bellybutton level. Hold a finger between the waist and the tape to get a more exact fit.
C. Hip size
Make sure your kid's feet are side by side and measure the hips where they are widest.
D. Inner leg length
Measure the inseam of the leg from the crotch straight down to the ground. You can also measure trousers that you know fit, from the crotch straight down to the end of the trouser leg.
E. Head size
Measure the head's circumference with a tape measure, just above the eyebrows, to get the the most accurate hat size.
F. Total height
Have your kid standing with their back against the wall, with their heels touching the wall. Measure from heel to crown, without their shoes on.