Height must be measured with the child standing barefoot. Keep both heels on the floor with the child’s back pressed against a wall. The child should stretch as tall as possible with the arms kept at the side while looking straight ahead. Move a square block of wood or a book down against the wall until it touches the top of the child’s head. Then measure the distance from the floor to the block of wood, to the nearest 1 mm, to get the correct height. Ideally, a special measuring device should be used, with a fixed tape or ruler on the wall and a sliding head board.
Under 2 years: It is difficult to measure an infant’s standing height. Therefore, the lying length is measured. If possible, a measuring board should be used. The infant is laid down on his/her back with legs fully extended. One person holds the infant’s head against the top board while another person gently stretches the infant’s legs, keeping the knees flat and pressing the heels of the infant’s feet against the bottom board. Measuring the distance, to the nearest 1 mm, between the boards gives the length of the infant. It is inaccurate to simply measure length with a tape measure.
For convenience, height is used in this unit. However, whatever is said about the height of older children, applies equally to the length of infants and young children.