To start, give the larger or more powerful army 10 tokens. Give the opposing army a proportional number of tokens. If one army has 10,000 men, for example, and the other has 7,000, give the smaller army seven tokens.

The Game Master will need to adjust for special or elite troops, better equipment, and so on. It's not important to count every point of armor and damage point–just get close enough to give a reasonable approximation of strength, adjust where needed, and trust in the dice and the player's actions to handle the rest.

Savage Worlds Deluxe Edition p. 106