When one side routs, retreats, or runs out of tokens, the battle ends and casualties are removed. Some of the troops lost in the battle can be recovered as they regroup or receive first aid.
If it's important to know how things stand after the fight, roll 1d6 for each token lost. The victor recovers a lost token on a roll of 4-6. The loser recovers a lost token on a roll of 5-6. A routed army recovers tokens only on a roll of 6.
After the battle and once both sides have figured out how many tokens they lost, remove the actual casualties from their armies. The side that started with the larger force simply multiplies the number of tokens lost by 10%. Losing four tokens, for example, means the entire army suffered 40% casualties. The side with the smaller force must figure out what percentage of his men are left. If he started with 8 tokens and ends up with only 2, for example, he's lost 75% of his force.
Once you've figured the total percentage of casualties to your army, distribute the losses among specific units as evenly as possible.
Savage Worlds Deluxe Edition p. 107