The formula for calculating the daily total amount of milk to feed:

$2.5 \text{oz/lb}$ which is approximately $160 \text{mL/kg}$.

If we are going for 3 hours per feeding, then in one day, we will have 8 feedings.

So for a baby that is $4 \text{kg}$ in weight, the total amount of milk to feed will be $640 \text{mL}$. Spread over 8 feedings, that makes $80 \text{mL/feeding}$.

Assuming we're going for 3 hours per feeding, here's a table that shows how much per feeding as a function of baby weight.