Military branches:
Army, Royal Navy (includes Royal Marines), Royal Air Force (2013)

Military service age and obligation:
16-33 years of age (officers 17-28) for voluntary military service (with parental consent under 18); no conscription; women serve in military services, but are excluded from ground combat positions and some naval postings; as of October 2009, women comprised 12.1% of officers and 9% of enlisted personnel in the regular forces; must be citizen of the UK, Commonwealth, or Republic of Ireland; reservists serve a minimum of 3 years, to age 45 or 55; 17 years 6 months of age for voluntary military service by Nepalese citizens in the Brigade of Gurkhas; 16-34 years of age for voluntary military service by Papua New Guinean citizens (2012)

Manpower available for military service:
males age 16-49: 14,856,917
females age 16-49: 14,307,316 (2010 est.)

Manpower fit for military service:
males age 16-49: 12,255,452
females age 16-49: 11,779,679 (2010 est.)

Manpower reaching militarily significant age annually:
male: 383,989
female: 365,491 (2010 est.)

Military expenditures:
2.49% of GDP (2012)
country comparison to the world: 28
2.48% of GDP (2011)
2.49% of GDP (2010)
[see also: Military expenditures country ranks ]