I have always implemented the Wilson Formular (or Andler) also known as the EOQ (Economic Order Quantity) as a customization.
The formula works with the empirical data and the bottom line is to find a optimal order quantity that minimizes the total inventory cost but max. service level. Several things are incl. in the variables, ramp up factor, service factor, order costs, storage cost, etc.
I can recommend the calculation with Excel - maybe- when it should be easy for the start. With the formula as mentioned above, you can build a solution on it. Here is an overview of what is considered in the formula, and how it looks like.
the formula should help
