Military Ranks (from Wikipedia)

Common military ranks
Officers
Navies	Armies	Air forces
Admiral of the Fleet	Field Marshal	Marshal of the Air Force
Admiral	General	Air Marshal
Commodore	Brigadier	Air Commodore
Captain	Colonel	Group Captain
Commander	Lt. Colonel	Wing Commander
Lt. Commander	Major / Commandant	Squadron Leader
Lieutenant	Captain	Flight Lieutenant
Sub-Lieutenant	Lieutenant	Flying Officer
Ensign	2nd Lieutenant	Pilot Officer
Midshipman	Officer Cadet	Officer Cadet
Seamen, soldiers and airmen
Warrant Officer	Sergeant Major	Warrant Officer
Petty Officer	Sergeant	Sergeant
Leading Seaman	Corporal	Corporal
Seaman	Private	Aircraftman