China and India are the global superpowers in terms of armed personnel, with 2.99 mil and 2.75 mil soldiers at the end of 2013; however, one has to add that a quarter of Chinese and more than a half of Indian armed personnel are reserve personnel. With more than 1.75 mil reserve personnel, the Indian Army is therefore the world's largest standing volunteer army.
As we all know, the size is often not everything. The quality of army is a function of many ingredients, such as training, leadership, technical development, or the compensation of armed personnel, for example.
Here is Historum's list of the Top 10 armies in the world's history:
1) Ancient Macedonian army （4th Century BC）
2) Roman Army (1st Century BC - 3rd Century)
3) Hun Army (3th - 4th Century)
4) Arab Army （7th - 9th Century)
5) Mongolian Army (13th - 16th Century)
6) Turkish Army (15th - 16th Century)
7) Russian Cossacks (17th - 20th Century)
8) French Army （19th Century)
9) British Army （20th Century)
10) US Army (20th - 21st Century)
Download data for all countries at Armed Personnel