We’ve all seen it at some point: a military story where an aging gray-haired major advises a prominent general or main character. Problem is, it can’t happen. There’s this little-known clause in military service that states any ‘regular’ officer (Major or above) who’s not being promoted higher must retire from service after 20 yrs. For majors and lieutenant commanders, that age is generally forty-two. If you haven’t been promoted out of those ranks by that age, you’re out of the military. Fact is, majors and lieutenant commanders are in their thirties. Most make that rank around the age of thirty-two, and they remain in that rank for about 5 years. These are things a civilian writer needs to know if he/she’s going to include a military aspect to their story. That specialized knowledge is what this article’s about.

Being passed over for promotion twice usually results in being dismissed from the military for the good of the service

There are two career paths in military service: commissioned officers and enlisted (including non-commissioned officers). A commission is something one receives from the government as a result of having a college education prior to entering the service, and puts you on the hook for leading others. In contrast, a non-commissioned officer (non-com, noncom or NCO) started out as a raw recruit and earned his/her stripes as an apprentice [think privates, specialists and corporals in the ground forces and seamen (classes 1-3) in seaborne forces]. Those ranks are apprenticeships in which the individual is learning his/her chosen trade. By the time they earn the 3 stripes of a sergeant or petty officer they’ve learned their trade and are considered journeymen. This puts them around 21, just shy of the age of a newly-commissioned officer (2nd lieutenant in the Army; ensign in the Navy).

In general, military ranks and ratings come with time limits to ensure a person gains the experience necessary for the new rank, and also to ensure he/she promotes to the next rank properly. Being passed over for promotion twice usually results in being dismissed from the military for the good of the service. In the lists below, each rank shows the minimum Time-in-Service (TIS) requirements to reach that rank.


Army Enlisted (assumes age 18 upon entering service):

  • E-1 (Private) – 0 TIS
  • E-2 (Private Second Class) – 6 months TIS
  • E-3 (Private First Class) – 1 year TIS
  • E-4 (Specialist/Corporal) – 26 months TIS
  • E-5 (Sergeant) – 3 years TIS
  • E-6 (Staff Sergeant) – 7-8.5 years TIS

For E-7 through E-9, simply meeting the minimum TIS requirements is not enough to attain those ranks:

  • E-7 (Sergeant First Class) – at least 6 years, but typically 13.5 yrs TIS
  • E-8 (Master Sergeant/First Sergeant) – at least 8 years, but typically 17 yrs TIS
  • E-9 (Sergeant Major) – at least 9 years, but typically 20.5 yrs TIS

Navy Enlisted:

  • E-1 (Seaman Recruit) – 0 TIS
  • E-2 (Seaman Apprentice) – 9 months TIS
  • E-3 (Seaman) – 18 months TIS
  • E-4 (Petty Officer Third Class) – 2 years TIS
  • E-5 (Petty Officer Second Class) – 3 years TIS
  • E-6 (Petty Officer First Class) – 6 years TIS
  • E-7 (Chief Petty Officer) – 9 years TIS
  • E-8 (Senior Chief Petty Officer) – 12 years TIS
  • E-9 (Master Chief Petty Officer) – 15 years TIS

Commissioned Officers

Now when you’re talking officers, start at age 22:

  • O-1 (2nd Lieutenant/Ensign) – 0 TIS
  • O-2 (1st Lieutenant/Lieutenant J.G.) – 18/24 months TIS
  • O-3 (Captain/Lieutenant) – 4 years TIS
  • O-4 (Major/Lieutenant Commander) – 9/11 years TIS
  • O-5 (Lieutenant Colonel/Commander) – 15/17 years TIS
  • O-6 (Colonel/Captain) – 21/23 years TIS

Anything at or above O-7 is political, so there’s no average age or TIS available.

Kinda confusing, ain’t it? And did you notice there are several flavors of ‘lieutenant’ and two mentions of ‘captain’ at conflicting points on the list?

First of all, the word ‘lieutenant’ means ‘a junior officer who acts on behalf of a more senior officer’ (or: tenant in lieu of). For this reason, militaries around the world are fond of using ‘lieutenant’ to indicate a junior variant of certain ranks. Hence, ‘lieutenant commander’, ‘lieutenant colonel’ and even ‘lieutenant general’. On a curious note, ‘lieutenant commander’ actually carries two meanings that end up amounting to the same thing. It can be seen as either ‘one who commands lieutenants’, or ‘one who acts on behalf of a commander’. Either way, the role is the same.

Not too many civilians understand that a captain in the Army would be a lieutenant in the Navy, but a captain in the Navy would be a colonel in the Army

And then there’s the case of the two captains. Not too many civilians understand that a captain in the Army would be a lieutenant in the Navy, but a captain in the Navy would be a colonel in the Army (they also have different abbreviations: ‘CPT’ for Army; ‘CAPT’ for Navy). Distinctions like these confuse plenty of writers, so to clear it all up here’s an officer chart that makes a handy companion. Download it and keep it ready for when your muse decides to wax military:


It should be noted that many navies list O-7 (Rear Admiral Lower Half) as ‘Commodore’ (typically abbreviated as CMDRE or CDRE). The US Navy has an on-again/off-again relationship with the rank of commodore. At the moment, they’re not on speaking terms.

Warrant Officers

And on top of all this, there’s the Warrant Officer (WO) and Chief Warrant Officer (CWO). These highly-skilled single-track specialists bridge the gap between enlisted and officers and exist for a very specific purpose. Most often, warrant officers (W-1) and chief warrant officers (W-2 through W-5) are promoted from the senior enlisted ranks to maintain their specializations and not risk being transferred to unrelated positions. However, the US Army recruits qualified high school graduates as Flight Warrant Officers (FWO) to pilot helicopters. Either way, warrant officers are senior to all NCOs and junior to commissioned officers. The warrant, as distinguished from an officer’s commission, comes from the secretary of that branch (Secretary of the Army/Navy, etc.) with the lone exception of the US Air Force, which ignores the WO/CWO ranks altogether in favor of senior/chief master sergeants (E-9/E-10 respectively).

A word (or many) about naval commands

Lastly, writers creating naval fiction should understand that any officer placed in command of a ship is its ‘captain’ regardless of their official rank. This is because ‘captain’ is both a formal pay grade but also a title of respect, which can get confusing when someone of non-captain rank is in charge; for instance, a commander.

To the crew, Commander X is considered the captain because he’s master of the ship; but he’s simply a commander to everyone else. This is also true for lieutenant commanders and lieutenants (although lieutenants only command vessels of less tonnage than ship classes). Of course, the opposite is true of anyone above the rank of captain who takes command of a ship, in which case the crew will address that officer by his/her official rank (commodore, admiral, etc.).

There’s more to say about the nuances of military hierarchy, but this is a decent start. I hope it helps.


Michael is author of the Soulstice Saga, a transcendental ‘spacetime’ opera. He lives in an increasingly entropic system listed as’ Denver’ without the slightest clue how he got there. He considers Australia’s fortunate blending of Grenache and Shiraz to be clear evidence of intelligent design, and credits it with his continued sanity.