It is the standard of what you would think most armies would have:
SMALLEST TO LARGEST: Squad(12-15 men), Platoon(30-60 men), Company(100-200 men), Battalion(500-800 men), Regiment(1200-2000 men), Brigade(3000-6000 men), Division(10,000-30,000 men), Field Army(50,000+, being the largest unit in our army).