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.
C. Seat size
Make sure your baby’s feet are side by side and measure around the fullest part of the seat.
D. Inner leg length
Measure the inseam of your baby’s leg from the crotch straight down to the ground.
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
Measure your baby from heel to crown, without the shoes.