As at 1 July 2016, there were 185,310 serving members of the Armed Forces with 57,590 dependent children.
Individual Service personnel self-declare the number of children they have on the Joint Personnel Administration (JPA) database. For the purposes of this question, a dependent child is defined as any child under the age of 18, as recorded on JPA. Numbers are rounded to the nearest 10. Numbers ending in 5 are rounded to the nearest 20 to avoid systematic bias.