How to Use the Internet Based Reverse Dynamic Safety Stock Calculator

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Executive Summary

This is the reverse dynamic safety stock calculator.
This puts a slight twist on dynamic safety stock.

Introduction to the Reverse Safety Stock Calculator

This dynamic safety stock calculator is designed to do the following:

Calculate safety stock.
Explain the logic behind the mathematics of the dynamic safety stock calculator.

See our references for this article and related articles at this link.

Every safety stock calculator that I was able to find uses the traditional calculation where the final output is the safety stock level. Sometimes you want to set an inventory level, and then see what the service level will be. This is the exact opposite or reverse of how the dynamic safety stock formula calculates.

The dynamic safety stock formula does not provide an easy way to do this. Through a slight adjustment, I have enabled this. It is determined by using this calculation form – although it is a two-step rather than one step process.

What This Safety Stock Calculator Is

The standard dynamic safety stock calculator is problematic in actual usage. For this reason, I created this safety stock calculator, which adopts some of the same concepts. But it provides more consistent output. Currently, the calculator does not include lead time variability. In most cases, the vast majority of variability is from the demand rather than the lead time side.

How the Safety Stock Calculator Form Works

This form requires input to provide output. However, it also has default values. You can change any input value and the rest of the formula — the output will change immediately. You can continue making changes, and the form will always update without having to press any button or refresh.

Steps to Using the Form

The form requires that you first submit the input.
Next, check if the safety stock difference between the calculated value and the safety stock you enter is positive or negative.
It then requires that you adjust the service level until you have a small safety stock difference. This is then the service level you can expect from the safety stock which you have entered.

Note: For some reason, the drop-down field below does not appear to work in Firefox – so if you are using that browser, try a different one. Second, when you enter a decimal into the Standard Deviation of Demand and Standard Deviation of Lead Time, you may receive a message “Please enter only digits.” You can ignore that message. The calculator works fine with a decimal point.

For the standard dynamic safety, stock calculator see this article.