Squad- Smallest unit, made of 9-10 soldiers and commanded by a sergeant or staff sergeant.
Platoon- 16-44 soldiers, lead by a Lieutenant w/ and NCO as second in command. Consists of two to four squads.
Company- 62-190 soldiers, or three to five platoons. Commanded by a captain w/ a first sergeant as the principle NCO. Armored or air cavelry unit of this size is called a troop
Battalion- 300-1000 soldiers, four to six companies. Commanded by a LtCol, capable of independant operations for a limited duration. Cavalry units of this size are called squadrons.
Brigade- 3000-5000 soldiers. Commands two to five combat battalions. Commanded by a Col. Armored cav, ranger and special forces units of this size are regiments
Division- 10,000-15,000 soldiers. Usually consists of three brigades, commanded by a major general.
Corps- 20,000-45,000 soldiers. Two to five divisions are a corps, and are commanded by a Lt. General.
Army- 50,000+ soldiers. Two or more corps Commanded by a Lt. General or higher.
I'm too tired to type out the command structure for the USAF
, just go here:
And if you really want to hurt your head, look at the USN
's operating structure: