Military expenditures:
2.67% of GDP (2018 est.)
3.11% of GDP (2017 est.)
2.97% of GDP (2016 est.)
2.76% of GDP (2015 est.)
2.28% of GDP (2014 est.)
(Estimates)
country comparison to the world (CIA rank, may be based on non-current data): 30
[see also: Military expenditures country ranks ]

Military forces:
Islamic Republic of Iran Regular Forces (Artesh): Ground Forces, Navy (includes marines), Air Force, Air Defense Forces; Islamic Revolutionary Guard Corps (Sepah, IRGC): Ground Forces, Navy (includes marines), Aerospace Force (controls strategic missile force), Qods Force (special operations), Cyber Command, Basij Paramilitary Forces (Popular Mobilization Army); Law Enforcement Forces (border and security troops, assigned to the armed forces in wartime) (2019)

Military service age and obligation:
18 years of age for compulsory military service; 16 years of age for volunteers; 17 years of age for Law Enforcement Forces; 15 years of age for Basij Forces (Popular Mobilization Army); conscript military service obligation is 18-24 months; women exempt from military service (2019)

Maritime threats:
the Maritime Administration of the US Department of Transportation has issued a Maritime Advisory (2019-012-Persian Gulf, Strait of Hormuz, Gulf of Oman, Arabian Sea, Red Sea-Threats to US and International Shipping from Iran) effective 7 August 2019, which states in part that "heightened military activities and increased political tensions in this region continue to present risk to commercial shipping...there is a continued possibility that Iran and/or its regional proxies could take actions against US and partner interests in the region;" at present, Iran has seized two foreign-flagged tankers in the Persian Gulf; the US and UK navies have established Operation Sentinel to provide escorts for commercial shipping transiting the Persian Gulf, Strait of Hormuz, and Gulf of Oman