The Kurukshetra war which lasted a mere eighteen days resulted in many losing their lives. The war could have been averted had Dhritarashtra been sensible and advised his sons to make peace with the Pandavas. But he did not. He realised his folly after the war was over, and the Kauravas were dead. He said to Sanjaya that he had had many indications that the war was going to end in victory for the Pandavas, and yet he had not paid heed to these indications. One of the indications was the support the Pandavas had from other kings. The Pandavas had the help of the Panchala king and the Matsya king. The Pandavas had been in exile for a long time, and yet they had the support of seven akshauhinis, said Kidambi Narayanan in a discourse.
What is an akshauhini? One calculation shows how an akshauhini is measured. A fundamental unit in the army had one chariot, one elephant, five foot soldiers and three horses. Three such units made up a senamukha. Three senamukhas made a gulma; three gulmas add up to a gana; three ganas made a vahini; three vahinis made up a brudhana; three brudhanas made a samu; three samus made an anikini and ten anikinis made an akshauhini. Another calculation of akshauhini says that one akshauhini had 21,870 chariots, 21,870 elephants, 1,09,350 soldiers and 65,610 horses.
The Pandavas had seven such akshauhinis. So these calculations give us an idea of the size of the Pandava army. The Kauravas did not have the support of as many kings as the Pandavas had. But they too must have had a large army. When the two armies clashed, the loss of human life was immense. This is what later left a victorious Yudhishthira unhappy. He could not celebrate his victory, for his subjects had lost dear ones. No one was left untouched by the horrors of the war.