When should an officer expect to be promoted to Captain?

Back in the dark ages when I was in it was automatic 1LT in 18 months, Capt in 3 years. The first competitive rank was Major, which if I recall correctly was considered at the 7 year point.

However, during the mobilization for the Viet Nam War there was a lot of churn of personnel into and out of the service - before the all-volunteer force.

Which state are you in brother? For the ARNG: 18 months to 1LT, 2.5 years to CPT in a decent sized State with vacancy promotions and a personnel section that is on the ball.

54 States & Territories mean the promotion rates vary widely. In general the ARNG has an issue filling captain vacancies and is well over strength on basic branch lieutenants. Very often its a battalion or brigade commander that will have a 1LT wait in line for the PL, XO Command time rather than to let the 1LT vacancy promote into a CPT slot outside of the brigade (training officer at the RTI or some such). States with small force structure (like Maine...so I've heard) must hold promotions on 1LTs as there isn't enough CPT positions to feed everyone in due time. A few years back I heard of a policy that held 1LTs as far as 4 years.

The States can make the problem worse by mismanagement of the State OCS program. An enlisted Engineer goes to OCS and wants to go Engineer after commissioning. The State will often honor it even if its full up on engineers and short on Air Defense with he 2nd order effect that it boogers up good promotion times for the Engineers of that cohort.

CPT (Join to see) While many things about the Active Army, Army National Guard, and Army Reserves are similar... over my career I learned two things are very different, and are also different between the Guard and Reserves. That would be promotions (all personnel systems) and military pay.

For the active Army it varies based the needs the of the Army.... The average is 36-48 months, but that all depends on the vacancies and requirements. At the height of the Surge in Iraq, all AD promotions expanded and accelerated. We are getting back to normal now, which means slowing and waiting longer...

I would recommend you talk your S1 folks, and if necessary the State J1. AR 600-8-29 (Officer Promotions) and Army Regulation 135–155 (Guard and Reserve Officer Promotions).

But, in the end promotion timelines are based on needs and vacancies.

I believe is promotions are based on Branch requirements, therefore those Branches with vacancies will have shorter times and as compare too those with excess officers.

Very good Read thank you for the Share CPT (Join to see)

With you, May take 5 years. Dumb question. No wonder I smiled when as a CWO I smiled when I saluted. The cut line is major. Get your stuff together LT.

Back in my day, the you could expect that promotion at about 3 years. I don't know what it is now.

When he starts putting cover sheets on the TPS reports.

High speed 3.5 years. Might not happen with less deployments and different Army. Might be 4 years now with a few more months as a 1LT. Butterbar to 1LT is pretty standard though still.

I cannot really speak to the USAR or to the ARNG as my commissioned promotions were on active duty. Nevertheless the last I heard they were both about 1 year longer before you entered the "in-the-zone" promotion area. When I was last deployed in 2007 most individuals were promoted to CPT on or about their 6th anniversary of commissioned service. For "below the zone" they were considered in their 4th year of commissioned service. Let's not even consider other promotion pathways.
I have glanced at what appears to be your official photo. The CIB helps, as does parachutist (especially with a star), pathfinder, and Ranger school especially is really helpful. You have four rows of decorations which screams competance as an NCO. I assume you had command of an Infantry Platoon as a 2/LT and now you are doing your staff rotation as a 1/LT. Unless your CO is a real pain, I would discuss with him the possibility of a below-the-zone consideration. If you are already in your fourth year and a reservist do the same. Several things will help (but you may have already taken care of these) ... smooth off any rough edges you may have, cultivate a larger vocabulary, purchase "Effective Phrases for Performance Evaluation", purchase SMARTbooks for your current position and what you wish to do. It is important that you make every effort to use the proper tenses of words. For example, it is never "me and John" (John and I or John and me), "John & me are friends" (John is my friend), "we was going" (we were going), " John ... he disrespected me" (John was disrespectful towards me) NOTE: I have seen errors such as these from honors graduates of Harvard and William & Mary so they are very common today and my suggestion is in no way a "put down". Take a public speaking class where you will actually be required to address a group. Learn Arabic and if possible, Farsi and Urdu/Hindustani.
Your security clearance transfers, so if you can reach TS-SCI do so. Now this next recommendation can be really hard depending upon your personal or family situation ... if you really want to command a 1st class "high speed-low drag" battalion in the Army, go on active duty before the end of your second year as a CPT. The earlier the better. If you are in SUPER shape approaching CPT America level, you can try out for "the Unit" or "the Activity" (the latter if you are imore interested in intelligence work than being a trigger puller). It is much easier getting into the unit if you have had an assignment to one of the actual Ranger BNs, and/or are SF qualified with some "gray" or "black" unit experience. Don't forget the Company. Within the National Clandestine Service is the Special Activities Division. If GAG and DEVGRU are the tip of the spear, these folks are the 1st three molocules on the tip. They most often take their recruits from the unit, the activity, the 75th Recon CO, DEVGRU, MARSOC, and the 24th STS. That does not mean however, that they would not take someone with your background if you can make the grade. Selection is extremely arduous and there never was (to the best of my information) a PC easy way to get certian persons into SAD. As an officer with NCO combat experience you will generally have more common sense than officers without that experience. Use that common sense at all times.
Final point ... when you are in your 50s and retired from the Army or whatever, you will regret all the time you could have spent with your children (assuming you have some of course). Spouses of course are a bit more problematic in SO personnel. All the excitement, adrenalin, decorations, honors, and money from follow on positions will not make up for the lost months or years of family life. This is the GREAT LESSON that we all have had to learn the hard way. I would spare you that regret.
It was not my intention to go so far afield, but I hope it proves useful to you in some way. Please contact me via message with comments, questions, and criticisms.