Most children double their weight from birth to 6 months and treble (increase by three times) their birth weight by one year. The increase in weight and height is fastest in the first year of life and then slows down until puberty when growth is again fast for a short while. Growth in head size is almost complete by 2 years.
Only when a child reaches 4 years is the birth length doubled. Thereafter the normal increase in height during childhood is approximately 4 cm per year.