As of June 20, 2014, the population of children age 14 and under in the United Kingdom was 10,941,339. This figure represents 17.3 percent of the overall population.
If the 0- to 14-year-old range is broken up into three equal age groups, the 0- to 4-year-old age group is largest, with approximately 4.2 million children. This is well over one third of all children in the U.K. In contrast, the 10- to 14-year-old age group accounts for approximately 3.4 million children, which is less than one third.
The gender ratio of children ages 0 to 14 in the U.K. is approximately 1.05 boys for every girl.