How many men are there in a brigade, division, so on and so forth. I know that the nhumbers can vary, but what would be the rough pattern, and so on.
Well, as guidelines you can look to this…
A fireteam is 4 to 6 guys with a light machine gun commanded by a corporal.
A squad is about a dozen guys with two fireteams commanded by a sergeant.
A platoon is three squads plus a headquarters element for a total of 30 to 40 commanded by a lieutenant.
A company (or a troop or a battery) is three platoons plus headquarters for a total of 150 to 200 commanded by a captain.
A battalion has three or four companies plus headquarters for a total of 300 to 800 or so, commanded by a lieutenant colonel.
A Brigade (or a Regiment in the Marines, same thing in American usages) is three or more battalions plus headquarters we are looking at 600 to 2000 soldiers commanded by a colonel
A Division has three or more Brigade/Regiments for a total of 10 to 20 thousand guys commanded by a major general.
A Corps has to or more divisions plus various other units figure on 30 to 50 thousand guys commanded by a lieutenant general.
An Army has a couple of Corps so we are in the 100 thousand range and a general at the top.
An Army Group has a few Armies and needs a general at the front of the parade.
Your milage may vary. This stuff changes throughout history and geography wildly.
With elite forces, the numbers go down, and the ranks go up.
Tris