Captain ( United States ) In the uniformed services of the United States , captain is a federal commissioned officer rank . U . S . Army , U . S . Air Force , and U . S . Marine Corps . In the United States Army , the United States Marine Corps , and the United States Air Force , captain is a company grade officer rank , with the pay grade of O - 3 . It ranks above first lieutenant and below major . It is equivalent to the rank of lieutenant in the other uniformed services . The insignia for the rank consists of two silver bars , with slight stylized differences between the Army / Air Force version and the Marine Corps version . An Army or Marine captain generally commands company - sized units . When given such a command , they bear the title Company Commander . Captains also instruct at service schools and combat training centers and are often staff officers at the battalion level . Marine captains also serve as Officer Selection Officers , commanding recruiting stations for commissioned officers . An Air Force captain ' s authority varies by group assignment . In an operations group , senior captains may be flight commanders while more junior captains may be heads of departments . In the maintenance or logistics and mission support groups they are almost always flight commanders . In the medical group , captains usually have limited administrative and command responsibility as captain is frequently the entry level rank for most medical officers and dental officers . In Army and Air Force medical units , captain is the entry - level rank for those possessing a doctorate in a healthcare related profession . In Army and Air Force Judge Advocate General units , captain or first lieutenant is the entry - level rank for lawyers who already have their Juris Doctor degree and have been admitted to the bar of at least one U . S . state or territory . MARSOC s fourteen man Marine Special Operations Teams ( MSOT ) are commanded by a captain . U . S . Navy , U . S . Coast Guard , U . S . Public Health Service , and National Oceanic and Atmospheric Administration . In the United States Navy , the United States Coast Guard , the United States Public Health Service Commissioned Corps , and the National Oceanic and Atmospheric Administration Commissioned Corps , captain ( CAPT ) is a senior officer rank , with the pay grade of O - 6 . It ranks above commander and below rear admiral ( lower half ) . It is equivalent to the rank of colonel in the other uniformed services . Navy captains with sea commands in the Surface Warfare community generally command ships of cruiser size or larger . The more senior the officer , the larger the ship . In the submarine community , a captain will typically command a ballistic - missile submarine ( SSBN ) , or a squadron of attack submarines ( SSN ) . In Naval Aviation , captains with sea commands generally command aircraft carriers , air - capable amphibious assault ships , carrier air wings , functional air wings or special mission air wings or air groups . Commanders of aircraft carrier strike groups and expeditionary strike groups are normally rear admiral s , while subordinate destroyer squadron commodores , amphibious squadron commodores , carrier air wing commanders and the individual ship commanding officers within the strike group are of captain rank or lower . In rare instances , the carrier air wing commander may be a Marine Corps colonel who is a Naval Aviator or Naval Flight Officer , while in the expeditionary strike group , the Marine Expeditionary Unit commanding officer will be a Marine Corps colonel . Navy captains who are line officers may also fill important senior staff positions or have shore based command assignments , such as commanding officer of naval stations , naval air stations , naval air facilities , naval support activities , logistics groups , specialized centers or schools , or commanders of test wings or training air wings . Staff corps captains will command facilities and organizations appropriate to their designators , such as naval hospitals commanded by medical corps , dental corps , medical service corps or nurse corps officers ; supply centers by supply corps officers ; or trial service offices commanded by judge advocate general corps officers . Coast Guard captains follow career paths very similar to their Navy counterparts , with seagoing officers typically commanding large maritime security cutter s or high endurance cutter s and aviators commanding coast guard air stations . Coast Guard captains will also command all types of major Coast Guard shore installations and activities , as well as serve as chiefs of staff for Coast Guard flag officers . The Coast Guard has no staff corps officers . PHS and NOAA captains are senior non - combatant officers that serve as directors or ranking supervisors in their respective Uniformed Service Corps . Seagoing NOAA captains will also command certain NOAA ships , while NOAA aviators will command NOAA flight operations activities . United States Maritime Service . Although it exists largely as a maritime training organization , the U . S . Maritime Service does use the rank of captain . Even though the Martime Service is an auxiliary service , the grade is appointed by the President via the Secretary of Transportation , making it a federally recognized rank with corresponding paygrade of O - 6 . Rank equivalency between services . Due to the ambiguity created by the common use of " captain " for officers of different grades between the Army , Navy , Air Force , Marine Corps , and Coast Guard , equivalency is conferred between officers by use of identical pay grade rather than title of rank . The higher the grade , the higher the rank of the officer . For example , an Army , Air Force , or Marine captain is equivalent in rank , responsibilities , and grade to a Navy or Coast Guard lieutenant , all of which are of the third officer grade , or O - 3 . Similarly , a Navy or Coast Guard captain is equivalent in rank , responsibilities , and grade to an Army , Air Force , or Marine colonel , all of which are of the sixth officer grade , or O - 6 . Thus , Army , Air Force , and Marine colonels together with Navy and Coast Guard captains wear the silver eagle insignia of the grade of O - 6 , while Army , Air Force , and Marine captains together with Navy and Coast Guard lieutenants wear the double silver bars of the rank insignia of the grade of O - 3 . Additionally , the O - 6 rank of Navy and Coast Guard captain is abbreviated as uppercase " CAPT " , while the O - 3 rank of captain is abbreviated as " CPT " for the Army and lowercase " Capt " for the Air Force and Marine Corps . Early history . In the United States , the rank of captain first appeared in the Continental Army during the Revolutionary War . A captain was the officer placed in charge of a company of soldiers and was granted a commission from the regimental Colonel . A captain was afforded one to several Lieutenant s , depending on the size of the company , and the captain ’ s commission could be revoked or expired at the end of a particular military campaign . The Continental Navy used the rank of captain as the commander of a sailing vessel at war , with the captain having several lieutenants on board , as well as a Sailing Master to assist in their duties . This use of the rank carried over into the U . S . Navy . With the addition of the ranks of commander and lieutenant commander between lieutenant and captain , a Navy captain became equivalent in rank to an Army colonel .