Starfleet ranks
Starfleet ranks were identifying titles of rank for the officers and enlisted members of Starfleet denoting the chain of command under both United Earth and the United Federation of Planets. These titles were generally adapted from earlier Earth naval forces. (, )

Early usage 
By the development of the NX-Alpha in 2143, Starfleet rank structure had at least three enlisted positions, four officer ranks, and three ranks for use by flag officers. Rank was displayed on the right breast of the s, above a colored shoulder trim denoting what department the crew member was assigned to (command gold, operations red, or sciences blue.) (, et al.) This insignia and system was still in place in 2161. ()

23rd century

Early 23rd century
By the 2230s, the Starfleet uniform used a sleeve stripe system instead of pips to denote rank. ()

Early-mid 23rd century

By 2239, Starfleet had adopted  where officer rank was denoted by the number of raised or indented pips on a delta shield badge of the Starfleet insignia, featuring an icon representing their division. () Command wore a golden shield with a five-point star, operations wore a bronze shield with an angular swirl, sciences wore a silver shield with a circular insignia, and medical wore a silver shield with a cross insignia. A captain's uniform also featured additional golden trim between the shoulders and the collar. (, et al.)

The Admiralty wore a Starfleet insignia surrounded by a wreath made up of smaller golden Starfleet insignias on a dark disc, with more insignia indicating a higher rank. ()

Another variation of this uniform introduced alongside this uniform in the 2250s changed the rank system back to a sleeve stripe system. ()

Another uniform used around this time had a much simpler rank and insignia system, in which enlisted personnel wore no rank insignia while the rank of chief petty officer was denoted by a special sleeve stripe. Commissioned officers wore a solid gold stripe. This system would be in use concurrently with other rank insignia systems for at least fifteen years, with only a slight modification in the early 2260s, when those holding the rank of captain were authorized to wear two gold stripes whereas other officers wore one. ()

By 2265, the rank system included another variety of sleeve stripes. ()

Late-mid 23rd century
By 2266, Starfleet had once again changed its uniforms and, while still using the sleeve stripe system to denote rank, the rank stripes had been modified to show more detail for each particular rank. An exception was that enlisted personnel, chief petty officers included, now had no insignia whatsoever with most enlisted personnel also wearing Starfleet jumpsuits instead of the standard tunic uniforms worn by the officers. ()

Starfleet flag officers wore a thicker braid insignia than regular officers. () 

The rank of cadet and midshipman were both in use at Starfleet Academy. ()

The 2266 rank and insignia pattern was as follows:

In the mid 2270s, Starfleet changed its uniforms again, although mainly in appearance only. The rank insignia of officers remained relatively the same, though the lieutenant junior grade braid was now used to indicate ensign. Enlisted personnel adopted a style of their own rank insignia and both officers and admirals could now wear a short sleeve "Class B" uniform which displayed rank insignia on shoulder tabs. ()

Late 23rd century
By the year 2278, Starfleet had again changed its uniforms, abandoning the previous sleeve stripe system and adopting a totally new insignia design which incorporated a series of rank pins worn on a shoulder strap with the color of the strap determining the bearer's branch within Starfleet. At this point, the lieutenant junior grade rank had also been re-established.

The shoulder strap system also matched with a cuff strap which could display various citation and years-of-service pins. Finally, in the case of admirals, another series of cuff straps denoted the particular rank of the admiral.

Enlisted uniforms were also completely revamped from previous versions and now were worn as jumpsuits with rank pins worn on the lower right sleeve. Enlisted ranks themselves were expanded, encompassing several grades of petty officer and chief petty officer. ()

With the exception of some minor cosmetic changes to officer uniforms, including the introduction of a standard communicator pin by 2344. () The uniforms and insignia of the late 23rd century remained unchanged until the late 2340s. ()

The insignia pattern was as follows:

24th century

By the year 2355, Starfleet had introduced a new uniform design, with a pip system of golden pin insignia worn on the collar. ()

The 24th century pip system included a black pip insignia to denote chief petty officers. ()

The pip system used in the mid-to-late 24th century remained relatively unchanged through 2385, having been kept across several uniform design changes. ()

In the 2360s, admirals wore a triangular insignia on a special flag officer uniform. ()

By 2365, this insignia had been replaced by a "boxed pip" system worn vertically on the flag uniform collar. () By 2366, the admiral insignia was commonly worn horizontally against the collar in the same way as the insignia worn by other grades. ()

By the mid-2370s, Starfleet had changed the chief petty officer rank insignia, replacing the hollow pip with chevrons and dots. ()

In the 2390s, Starfleet's familiar pip design for was now located on the right breast of the uniform instead of the collar, and the pips were now hemisphere-shaped and silver. () The pips of flag officers were placed on a dark gray isosceles trapezoid with a silver border. ()

32nd century
By the 32nd century, Starfleet had passed through a number of rank insignia systems. ()

By 3189, rank was indicated on an officer's tricom badge and collar. ()

Alternate timelines

Mirror universe

Alternate reality
By 2258 in the alternate reality, Starfleet had adopted uniforms and an insignia pattern reminiscent of the mid 2250s in the prime reality. These new insignia consisted of silver bands worn on the lower sleeves of the uniform. Ensigns and certain skirt uniforms displayed no rank insignia. ()

Alternate universe
In an alternate universe observed during a quantum fissure, Starfleet had adopted an additional form of insignia which was incorporated directly into the design of the Starfleet combadge. The insignia appeared as black, gold, and silver bars behind the Starfleet delta, designed to show the rank of the wearer and along with collar pips. ()

The same insignia was also used by the alien Barash during a holographic simulation of the USS Enterprise-D, designed to trick Commander William T. Riker into thinking he was in the future. Barash's simulation did not include the collar pips. ()

29th century 
The uniforms worn by the Starfleet crew of the  during the 29th century displayed rank insignia on the right collar. ()

Comparative rank tables

Flag officers
Admirals in Starfleet were described as the flag officers, a term held over from naval tradition. These ranks constituted the highest authorities of Starfleet Command. ()

Fleet admiralIn 2293, 2399, and 3189, the commanders in chief of Starfleet held this rank. (, , )

AdmiralNext below fleet admiral, above vice admiral. ()

Vice admiralNext below admiral, above rear admiral. ()

Rear admiralNext below vice admiral, above commodore. ()

CommodoreSuperior to captain, inferior to rear admiral. ()

Officer ranks
 Captain
The most senior regular officer rank below flag officer, it was most often held by starship and starbase commanders. (, et al) Captains could also serve as administrative adjutants beneath admirals. () In rare circumstances, officers with the rank of captain held other positions aboard a starship, such as "Captain of Engineering" Montgomery Scott aboard the , and later Scott and Spock aboard the Enterprise-A. () Phillipa Louvois held the rank of captain while working as a prosecutor under the office of the Judge Advocate General at Starbase 173. ()

 Commander
 The officer rank immediately above lieutenant commander, and below captain. Typical assignments at this rank included executive officer of larger vessels, space station commander (such as Benjamin Sisko of Deep Space 9). (, ) The rank of commander was also available to chief medical officers and ship counselors who passed the Bridge Officer's Test. ()

Lieutenant Commander
The officer rank immediately above lieutenant, and below commander. Officers with this rank could serve as the executive officer of smaller vessels. (, , ) In some cases, a lieutenant commander could also serve as the commanding officer of a smaller vessel, such as Worf or Jadzia Dax of the . (, )

Lieutenant
The officer rank immediately above lieutenant junior grade, and below lieutenant commander. Some advanced Starfleet training programs, such as Advanced Tactical Training, commissioned their graduates at this rank. ()

Lieutenant junior grade
The officer rank immediately above ensign, and below lieutenant. It was also the rank bestowed on medical doctors and counselors (but not nurses) upon completion of their studies and training at Starfleet Medical Academy or elsewhere. This rank acknowledged the additional time required to become commissioned as reflected in Beverly Crusher's service record and Julian Bashir's age as a recent Academy graduate. () Assistant counselor Ezri Dax skipped her final months of training and was explicitly given "commission as a full counselor with the rank of lieutenant (junior grade)." ()

Ensign
The most junior officer rank. It was the rank bestowed on newly-commissioned officers when they graduated from Starfleet Academy. () Ensigns who had distinguished themselves in their academy class or on duty could be posted as a senior bridge officer, such as Harry Kim. () A typical officer spent approximately three years at the rank of ensign. ()

Provisional officers

In 2364, Starfleet propulsion expert Kosinski ran several upgrade experiments on the Enterprise-D. Kosinski wore a unique rank insignia denoting his special position. ()

The crew of the USS Voyager, which included non-Starfleet Maquis members, was forced to make use of provisional rank appointments as a matter of course since the ship was stranded in the Delta Quadrant and the Maquis members were essential to shipboard operations. (, et al.)

Cadet ranks
Cadet ranks were held by those attending Starfleet Academy during their training to become commissioned officers. ()

Cadet 1st classCadets of this rank were fourth-year students at Starfleet Academy. After graduation, these cadets were granted the rank of ensign. (, )

 Cadet 2nd classCadets of this rank were third-year students at Starfleet Academy. ()

Cadet 3rd classCadets of this rank were second-year students at Starfleet Academy. ()

 Cadet 4th classCadets of this rank were first-year students at Starfleet Academy. ()

Enlisted ranks
Enlisted ranks were achieved by members of Starfleet who had not attended Starfleet Academy. ()

Non-commissioned officers
Master chief petty officer

Senior chief petty officerAlso known as "senior chief specialist". ()

Chief petty officer(, )

Petty officer
Petty officer, first class; also known as "technician first class", etc. ()
Petty officer, second class; also known as "specialist second class", etc.
Petty officer, third class; also known as "yeoman third class", etc. ()

Crewmen
Crewman
Crewman first class ()
 Crewman second class ()
Crewman third class ()

The lowest possible rank of recruit, ranked below the crewman grades. ()

Titles and positions

Fleet captain
Fleet captain was a title bestowed on senior Starfleet captains. It was a rare distinction, held by particularly distinguished captains. The title of fleet captain was held by former  Captain Christopher Pike in the year 2266. It was also held in the 2260s, by Captain Garth, one of Starfleet's most decorated captains and hero of the Battle of Axanar. ()

Deputy director

While posing as a deputy director with Internal Affairs, Luther Sloan wore captain's pips with a gold bar connecting them beneath. ()

Colonel

In 2293, Starfleet Colonel West was involved in the Khitomer conspiracy. ()

Corporal
In 2154, Starfleet Corporal Askwith perished at the Earth embassy on Vulcan. ()

Miscellaneous

In 2254, Captain Christopher Pike, while on Talos IV, imagined himself as an Orion trader. He imagined an officer in a dress uniform with him at the Orion colony wearing peculiar shoulder epaulets and of unknown rank. ()

In 2376, The Doctor aboard Voyager briefly resigned his Starfleet commission. ()

Appendices

See also
Starfleet admirals
 Starfleet captains
Starfleet commanders
 Starfleet lieutenant commanders
Starfleet lieutenants
Starfleet lieutenants junior grade
Starfleet ensigns
Starfleet cadets
Starfleet enlisted personnel
Starfleet crewmen

Background information
The rank system used during  was originally designed by William Ware Theiss, with the first versions inspired principally by the insignia of the United States Navy. According to Inside Star Trek: The Real Story, since Gene Roddenberry didn't want an overtly military Starfleet, Theiss toned down his stripe system by giving ensigns no stripe and lieutenants one full stripe, which is what an actual USN ensign wears.

For , Jon Povill sent Fletcher a production memo, dated , explaining the rank insignia to be used in the film, with no reference to lieutenant junior grade or other flag officers. (The Making of Star Trek: The Motion Picture, p. 126) Robert Fletcher, who designed the  used in the film, developed a rank system which displayed on straps over both shoulders. These insignia included a circle for "mid shipman", a triangle for "lieut comm jr. grade", a chevron for "lieutenant comm", a single stripe for "commander", two stripes for "captain", two stripes a circle with spines for "admiral" and two spiney circles for "adm of the fleet". (Star Trek: Costumes, p. 45) An unidentified triangular insignia is worn on the epaulets of several crewmembers, but is not identified in any production or background sources. It's A Wrap! sale and auction listed it as representing the rank of petty officer.  While an additional epaulet insignia featuring a single thin strip was also used but not identified to a rank. 

During the production of , Director Nicholas Meyer wanted the uniforms to feel as real as possible, and asked for new rank insignia. Fletcher explained: "There was kind of a complicated arrangement of divisions and ranks expressed by the braid on the sleeves. I made that up. I organized it and produced a little instruction booklet about it for the wardrobe department […]." On the early version of the uniforms, the insignia was on a band around the upper arm, which was later moved to the cuff.

The , depicted an overview of the rank system used in the , though it omitted the petty officer second class, created the master chief petty officer second class and fleet captain (which had not been used in the films,) and depicted erroneous insignia for lieutenant commander and admiral. The Star Trek Fact Files Part 70 and the , would also include the apocryphal fleet captain and master chief petty officer second class insignia, the erroneous lieutenant commander insignia (with a broken vertical gold stripe, instead of a solid horizontal gold stripe,) and an almost entirely different depiction of flag officer insignia. This system created an insignia with one gold dart to represent commodore, used the commodore insignia for rear admiral, created a three gold dart insignia for vice admiral, and used the rear admiral insignia for admiral. A three gold dart insignia was included in some It's A Wrap! sale and auction flag officer sets, but never seen on screen. 

The later pip designs of Star Trek: The Next Generation and Star Trek: Enterprise emulated US Navy insignias almost exactly, although an article on the 2151 uniforms and rank did not mention lieutenant junior grade or lieutenant commander. () Neither rank is used during Star Trek: Enterprise.

Warrant officers
According to the personal notes of the movie-era Starfleet ranks designer, Robert Fletcher, "there is no warrant rank." (p. 11)

A  '"Star Trek" Cast Ranks' memo from Rick Berman to Bill Theiss confirms the intention of having warrant ranks, whereas it was stated that the "C.W.O." ("Chief Warrant Officer") was described as having "1 Black Disk" (pip).

According to the , the insignia worn by CPO Miles O'Brien in Star Trek: Deep Space Nines first few years and enlisted Maquis on  was supposed to represent a warrant officer, even though numerous dialogue references and general naval parlance about the ranks of those referred to would seem to contradict this.

Apocrypha
The role-playing game supplement Star Trek: The Next Generation Officer's Manual discusses ranks.

Star Trek: Countdown to Darkness, Issue 2 depicts that a style of uniform was in use by 2239. This would make it seem that a few versions of the prime reality uniform were never adopted in the alternate reality, unless they was used very briefly after 2233.

A rank senior to fleet admiral was first referenced in "The Wormhole Connection". The rank of grand admiral is said to have existed in 2285 and has a special uniform with shoulder boards worn on the red maroon jacket uniform. The rank also appeared in the novel The Sorrows of Empire, held first by the counterpart Garth, then by the counterpart Matt Decker and then by , before he becomes Emperor of the Terran Empire.

A "flag admiral" insignia design (a six pointed starburst) from the fan-published Klingon Covert Operations Manual was used as one of Data's medals in .

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